Ruiz grew up in David, Panama, and was the oldest of three sons. His father was a police officer and his mother was an elementary school teacher. When he was seven years old, his father Joaquin was patrolling in his police jeep when a tire blew out, causing the vehicle to flip, throwing Joaquin into a ditch, and then crushing him when it fell on top of him. Just weeks before, his grandmother died of cancer. As a result, Ruiz became "the new father", starting work shortly thereafter as a laborer on a coffee farm to supplement the family income, and by age 10 was earning about US$3 per day. He also promised his widowed mother that he would make it to Major League Baseball to support the family. Subsequently, he began attending college to earn a degree in physical education, but dropped out shortly after he began to attend the Phillies baseball academy.
Ruiz's upbringing contributed to his approach to the game. His mother insisted that he excel academically, and would not allow him to play baseball unless he did well in school. Baseball was his first love, and he was responsible for organizing the community's games:
"Ruiz's natural leadership skills flourished. As a boy, Ruiz, who had chosen to play with baseballs instead of toy cars even as a toddler, was always the one in his neighborhood to organize pickup baseball games. It was he who brought the balls and bats, and it was he who picked the teams and ordered everyone to their positions. He had an acute understanding of the game. Ruiz was made to lead, and playing catcher eventually suited him perfectly."
In 1998, Ruiz followed his dream of playing professional baseball first by attending the Phillies Baseball Academy in La Vega, Dominican Republic, where he played catcher for the first time, moving from his initial position of second base. Though he was ready to quit because "he looked and felt like a 10-year-old among the tall, athletic prospects surrounding him", his uncle convinced him in a phone conversation to stick with it. The Phillies signed him as an amateur free agent on December 4, 1998 for US$8,000, and he made his professional debut in 1999 with the Dominican Summer League (DSL) team DSL Phillies, with whom he compiled a .305 batting average, 4 home runs, and 35 runs batted in (RBIs) in 60 games. Prior to the 2000 season, Ruiz met Mick Billmeyer, the Phillies' minor league catching coordinator, who served as his mentor. Billmeyer sought to learn Spanish while Ruiz sought to learn English, and the two bonded as Billmeyer helped mold Ruiz into an eventual top prospect and ultimately a starting catcher. In 2000, he came to America, progressing to play in the Gulf Coast League (GCL) for the GCL Phillies, and hitting .277 in 38 games. He earned another promotion in 2001, playing for the Lakewood BlueClaws of Class A Minor League Baseball. In 2001, his performance was similar in quality to his first two seasons, and he was promoted to the Clearwater Threshers of Class A Advanced, with whom he played over parts of the next two seasons. He struggled at the plate in 2002, compiling just a .213 batting average in 92 games, but hit .315 in 15 games in 2003, and that year earned another promotion.
In 2004, Ruiz spent the entire season with the Double-A Reading Phillies, posting a .284 batting average and hitting 17 home runs, the latter of which was second among catchers in the Eastern League. In addition to his strong offensive numbers, he threw out 25 of 76 attempted base stealers (32.9%). Off the field, it was in 2004 that Ruiz first gained the original form of his nickname "Chooch". Though a quiet individual, Ruiz frequently muttered "chucha" (a word equivalent to the f-bomb in Panama) under his breath, and teammate Anderson Machado thus began to address Ruiz as "chucha", which was later shortened to "Chooch", and the nickname's usage snowballed from there. His strong performance earned him another promotion in 2005 when he played for the Triple-A Scranton/Wilkes-Barre Red Barons, and posted a better batting average but fewer home runs than in Reading: .300, 4 home runs, 40 RBIs in 100 games. Before the 2006 season, he played for his native Panama in the first World Baseball Classic. His final season in the minor leagues was 2006. During 100 games, he hit .307 with 16 home runs and 69 RBIs, earning International League all-star accolades. He moved back and forth between Triple-A and the major league Phillies all year long, making his MLB debut on May 6, 2006.
Ruiz received his initial promotion to the major league level when Phillies' starting catcher Mike Lieberthal went to the disabled list (DL) in May 2006, and Ruiz debuted on May 6. After Lieberthal returned, Ruiz was sent back to the minor leagues. When Lieberthal went back to the DL in June, the Phillies utilized Sal Fasano and Chris Coste rather than recalling Ruiz. He was recalled on July 4, and hit his first major league home run that day off of San Diego Padres' pitcher Clay Hensley. He was optioned back to the minor leagues one more time before being recalled on August 31—essentially a September callup. Overall, with the big league club, he hit .261 with 3 home runs and 10 RBIs.
Ruiz permanently joined the major league roster on opening day 2007, having completed eight seasons in the minor leagues. He ultimately "grabbed hold of the top job [as starting catcher] and never let go". The Phillies signed Rod Barajas before the season because they had concerns about Ruiz' ability to catch, hit, and generally hold up over a full season at the major league level, as major league seasons are longer than minor league ones. During the season, he honed his confidence and earned the trust of the Phillies' pitching staff, including veteran Jamie Moyer, who commented, "I see a real assuredness to his body language. He's not cocky or brash. He just seems very confident in what's going on." On June 26, 2007, Ruiz stole home on the front end of a double steal in an 11–4 home win over the Cincinnati Reds, becoming the first Phillie to steal home since Scott Rolen in 1997. He ultimately played 115 games during the season, and from then on was the Phillies' undisputed starting catcher. Statistically, he committed only two errors, which tied for second-best among MLB catchers with at least 100 games played. He had 27 multi-hit games, hit 6 home runs and 51 RBIs with a .259 batting average. At the conclusion of the season, he was named to the Topps All-Star Rookie Team.
Ruiz entered the 2008 season focused predominantly on defense, specifically helping the pitcher:
"... Ruiz invests himself in the pitcher's performance. He and the pitcher succeed or fail together... Everything starts with pitching. 'Hitting is nice, but working with the pitcher is my No. 1 job. ... I want to feel like we are one person.'"
Ruiz struggled to hit consistently throughout the season, specifically in the first half; from the beginning of the year until July 11, he hit .206 with 2 home runs and 20 RBIs. Nevertheless, due to his rapport with the pitching staff (pitchers' ERA when throwing to him (catcher's ERA) was 3.56, the best for any catcher in the National League (NL)), and a vote of confidence from manager Charlie Manuel, he was secure in his position. In late July, he had a multi-hit game against the New York Mets, which may have helped him break out of his slump. Ultimately, during the regular season, he hit .219 with 4 home runs and 31 RBIs.
Despite his struggles at the plate during the regular season, Ruiz was an integral part of the Phillies' postseason success. After the Phillies clinched the 2008 National League Championship Series, he commented that the glory of winning a crucial baseball game that clinched the series, which he had witnessed while growing up in Panama on television, "happened to me", noting the aura of the moment, and that it culminated and validated the hard work he had put in over the years. Subsequently, in game 3 of the 2008 World Series, Ruiz tapped a ground ball up the third-base line for a walk-off infield single, the first in MLB history. Ruiz noted, "I heard them cheering. And that's when I knew, 'Okay it's over' ... I'll take a win." The Phillies eventually won the World Series for the first time since 1980, doing so in five games, the last of which began on October 27 and ended on October 29 after it was suspended part-way through due to rain. For his performance in the playoffs, he earned the nickname "Senor Octubre" (Mr. October in Spanish).
Initially, Ruiz decided not to play in the 2009 World Baseball Classic, but he received a call from Martin Torrijos, the President of Panama, and subsequently agreed to play for the Panamanian team. Early in the season, he suffered a muscle strain in his right oblique, which caused him to miss time while on the disabled list. Also early in the season, there was debate as to who the Phillies starting catcher should be – Ruiz or Chris Coste. Rob Neyer summarized the debate and ultimately endorsed Ruiz when he wrote,
"It's Ruiz who has established himself as the superior hitter, almost solely because we expect him to draw more walks than Coste. Yes, Coste does have superior stats as a major leaguer ... But he is 36, and with a couple of exceptions he's not fared all that well in the high minors. Meanwhile, Ruis [sic] is six years younger and he's been relatively impressive in the high minors."
Ultimately, Ruiz was the regular starter. He finished the season on a hot streak; over the final 24 games, he hit .355 with 9 doubles, 1 home run, 11 RBIs, and a .446 on-base percentage (OBP). In late September, he missed a week of games due to inflammation in his left wrist. Despite his missed time, he started 100 games, and set career highs in home runs (9) and base on balls (47), as well as posting a .255 batting average and 43 RBIs. Moreover, he walked more times than he struck out, a rare feat among modern major league hitters. In the postseason, he led the team with a .341 batting average, and recorded a .491 OBP, having reached base in each of the Phillies' 15 games, which perpetuated the usage of his nickname "Senor Octubre". Marcus Hayes of The Philadelphia Daily News wrote that Ruiz is, "... the Phillies' Senor Octubre, a No. 8 hitter who hits like John Buck in the regular season, then turns into Johnny Bench come autumn."
In 2010, Ruiz had a season filled with "indelible moments". He was catcher for Roy Halladay's perfect game on May 29, 2010 against the Florida Marlins and Halladay's no-hitter against the Cincinnati Reds in the first game of the National League Divisional Series on October 6, 2010, the first time a catcher had caught two no-hitters in one season since 1972. On May 4, he hit a walk-off home run, the second of his career, to lead the Phillies over the St. Louis Cardinals. Ruiz spent time on the DL in late June and early July with a concussion, but according to manager Charlie Manuel returned with a more efficient swing that allowed him to hit better against power pitchers. He led the team with a .302 batting average and a .400 on-base percentage. Both statistics also led National League catchers, and he even received a few votes for NL most valuable player. During the 2010 postseason, he did not perform as well as in past years—in nine games, he hit .192 with two home runs and four RBIs. Fans voted Ruiz the "X-Factor Player of the Year" in MLB's This Year in Baseball Awards. He also received the Pride of Philadelphia Award from the Philadelphia Sports Hall of Fame. Halladay called Ruiz a "rock" behind the plate, and presented him with a replica of his Cy Young Award.
Ruiz returned for the Phillies' 2011 season as their everyday starting catcher, and started 113 games, of which the Phillies won 70 (.619 winning percentage). In May, he spent time on the DL with inflammation in his lower back. Over the Phillies' final 36 games, he posted a .342 batting average. Overall, he finished with the best catcher's ERA in the major leagues (3.06), a .283 batting average, 6 home runs, and 40 RBIs. His batting average was second on the team trailing only Hunter Pence.
Ruiz began the 2012 season strongly, and throughout the season was a bright spot on an otherwise disappointing team. Through June 27, he led the Major Leagues with a .364 average. This contributed to a stellar first half of the season earned him his first placement on the National League All-Star team. He was a reserve, though some analysts, including ESPN's John Kruk, felt his numbers warranted a starting nod, which ultimately went to the San Francisco Giants' Buster Posey through the fan voting. Shortly after the announcement that he was an all-star, a piece in The Philadelphia Daily News entitled "The evolution of Carlos Ruiz" summarized his career: "Ruiz, though, was never a major prospect. He was a reserve catcher before he was a starting catcher. He was a bottom-of-the-order hitter before he was a middle-of-the-order hitter. And now, for the first time in his career, Carlos Ruiz is an All-Star." After the all-star break, he spent over a month on the disabled list with plantar fasciitis, hindering his statistical totals, which at the time of his injury were among the best in the National League. He led all NL catchers in doubles, en route to posting a .325 batting average with 16 home runs and 68 RBIs, all of which were career highs. He finished 28th in MVP voting, the third consecutive season he had received votes.
On November 27, 2012, Ruiz was suspended for 25 games without pay by the MLB for testing positive for an amphetamine called Adderall. The suspension of Ruiz was effective at the start of the 2013 season. Adderall is a drug prescribed for treating ADHD, described as a "central nervous system stimulant used to increase the attention span and decrease distractibility." He made his 2013 season debut on April 28 against the New York Mets at Citi Field. On May 20, he was placed on the DL with a Grade 2 strained hamstring. He came back with a four-hit game, which tied his career high, against the Los Angeles Dodgers on August 18, and hit .288 over the final two months of the season, commensurate with his past performance.
In the 2013 season, Ruiz compiled a .268 batting average, five home runs, and 37 RBIs in 92 games, his lowest major league total since 2006. After the season, Ruiz became a free agent. He re-signed on November 21, 2013 to a three-year contract worth US$26,000,000 plus a club option for a fourth season, giving the Phillies have an option to bring Ruiz back for a fourth season, at their discretion. Though one writer suggested his 2013 year might just have been an "aberration", most thought the Phillies overpaid to keep Ruiz, who turned 35 during the subsequent offseason.
Before the 2014 season, he received an exemption from MLB to use Adderall, an exemption given to nine percent of MLB players despite only four percent of the American population diagnosed with the condition. After a slow start, Ruiz earned NL player of the week accolades in late April after he hit .500 during a Phillies' road trip. He sustained a concussion on June 26 that forced him to go on the disabled list; he began a rehabilitation assignment on July 17 with the Clearwater Threshers. On September 1, Ruiz was behind the plate for the combined no-hitter thrown by Cole Hamels, Jake Diekman, Ken Giles, and Jonathan Papelbon in a 7-0 victory over the Atlanta Braves. It was the third no-hitter caught by Ruiz in his career, which ties him for second in Major League history behind Jason Varitek, who caught four. In 2014, Ruiz played 110 games batting .252 with six home runs and 31 RBI, and overall, had "a fine season ... [that] shouldn’t get lost amid the many negatives." On October 1, 2014, Ruiz underwent a minor arthroscopic shoulder surgery.
Cognizant of his increasing age and the wear catching places on one's body, the Phillies reduced Ruiz's workload during spring training, hoping to keep him fresh throughout the regular season. Regardless, he insisted upon catching pitchers' bullpen sessions so he could develop a feel and rapport with each pitcher. On July 25, Ruiz became the first catcher in the National League, and the second catcher in Major League Baseball history, to catch four no-hitters when teammate Cole Hamels no-hit the Chicago Cubs. Overall, Ruiz lost his starting job to Cameron Rupp, and had significant declines in many aspects of his game, particularly those at which he previously excelled, including framing pitches – in 2015, Baseball Prospectus ranked him worst in the league at doing so – and the mental aspect of the game, as he made several uncharacteristic errors.
Offensively, Ruiz developed from a "bottom-of-the-order hitter", to a patient hitter inclined to work the count, and finally to a hitter with solid gap-to-gap power. Ruiz has strong plate discipline that helps him draw walks and avoid strikeouts; he has almost as many walks as strikeouts over the course of his career, a rarity in the modern era of baseball. However, as his career progressed and he hit more towards the middle of the lineup, he has taken a more aggressive approach at the plate, and consequently he has struck out more often, but his home run totals have also increased. In 2014, his versatility and production at the plate encouraged his manager, Ryne Sandberg, to utilize him in various spots ranging from second through seventh in the batting order. At the prime of his career, he was among the best hitting catchers in MLB. Entering 2014, Ruiz had stolen only 16 bases over his first eight seasons; he had never been particularly fast, which initially caused his conversion from infielder to catcher, but because of his "hustle" on the basepaths, he won the Major League Baseball Players Alumni Association Heart and Hustle Award in 2012.
When catching, Ruiz seeks to become "one" with the day's pitcher; he takes their successes and failures personally, refusing to blame pitchers, and accepts equal responsibility. Phillies pitchers trust Ruiz and his ability to call games, and this ability's improvement has coincided with his increased proficiency in English. Cole Hamels attributes Ruiz's prowess in calling games to astute preparation, commenting,
"I think he's very aware of what the hitter is trying to do in each count. He gives you a good target. It's almost like he understands what you're thinking and he's speaking to you without saying anything. ... If a catcher can help you, it makes your job so much easier and he can do that so well."
Ruiz realizes the importance of his role with the Phillies, opining, "It's the catcher's job to bring energy and happiness to the game." Ruiz has a good throwing arm that has improved over the years; over the course of his career he has thrown out 29% of attempted base stealers, which is exactly the average percentage of hitters thrown out by catchers.
A Sports Illustrated piece featuring Ruiz published in July 2011 encapsulated Ruiz's role as "heart and soul" of the team:
He is a favorite among Phillies fans, and crossed "a cultural moat that Hispanic players often can't" to endear himself to not only the fan base, but also his teammates. Before games, he humorously imitates teammates to help keep the team loose and relaxed, furthering his role as a leader. Overall, Ruiz "is a man who refuses to conceal his emotions", positive or negative, and serves as a constant source of encouragement and rebuke alike to his teammates.