McReynolds was born in Little Rock, Arkansas.
He attended Sylvan Hills High School in Sherwood, Arkansas where he played baseball. McReynolds was said to be one of the best high school players in Arkansas. McReynolds proved that by hitting .638, 15 home runs, and had 60 RBIs during the first 25 games of his senior year. He led his Bears team to the Arkansas Class AAA State Baseball Championship and was Tournament MVP in 1978. McReynolds was named the 1978 Arkansas High School Baseball Player of the Year.
In 2011, McReynolds became the school's first inductee to the National High School Hall of Fame.
He was drafted by the Milwaukee Brewers after his senior year of high school, but chose to attend the University of Arkansas where he played outfielder for the Razorbacks under scholarship. At Arkansas, McReynolds proved that the Razorbacks made a good move in giving him that scholarship. In his freshman year McReynolds hit for a .282 batting average with eight home runs and 37 RBIs. That year Arkansas came in second in the College World Series in which McReynolds hit for a .566 batting average, with two home runs, two doubles and five RBIs. McReynolds got better as his college career progressed. In his junior year McReynolds hit for a .386 batting average with 17 home runs and 57 RBIs as the Razorbacks finished second in the league and received a berth in the NCAA tournament.
On June 1, 1981 McReynolds was drafted by the San Diego Padres with the sixth pick in the 1st round, and played in the minor leagues from 1981 to 1983. McReynolds played for the A+ Reno Padres in Reno, Nevada, the AA Amarillo Gold Sox in Amarillo, Texas and then the AAA Las Vegas Stars in Las Vegas. In 1983, during his time in Las Vegas, McReynolds won the Pacific Coast League MVP.
McReynolds made his major league debut for the Padres on June 2, 1983 against the Philadelphia Phillies. McReynolds finished the season with a .221 batting average, 4 home runs, and 14 RBIs.
In 1984, the Padres reached the World Series for the first time in franchise history. McReynolds along with rookie outfielder Carmelo Martínez was hyped as the M&M Boys after the New York Yankees 1960s power-hitting duo of Mickey Mantle and Roger Maris. McReynolds shared the team lead for home runs with 20 and Martinez was fourth on the team with 66 RBIs. During the 1984 National League Championship Series (NLCS) McReynolds had a .300 batting average, hit 1 home run and 4 RBIs. However, he broke his wrist trying to break up a double play in Game 4, and was out for the season. The Padres won Game 5 and advanced to the World Series, losing 4–1 to the Detroit Tigers.
On December 11, 1986 McReynolds along with two other players was traded to the New York Mets. There McReynolds continued to flourish as a major league ballplayer. His best season came in 1988. McReynolds tied his career high batting average with a .288 and set career highs in RBIs with 99 and stolen bases with 21, which set a Major League Baseball record for stolen bases without being caught stealing. That year McReynolds came in third in the MVP voting behind Kirk Gibson and Darryl Strawberry.
In 1988 the Mets made it to the NLCS against the Los Angeles Dodgers. McReynolds played fairly well in the series batting .250 with 2 home runs and 4 RBIs. In game 1 of the championship series McReynolds was famous for his collision with Dodgers catcher Mike Scioscia. This brought attention to McReynolds who was known for not wanting attention. McReynolds stayed out of the headlines for the rest of the series as the Mets lost the series by a series score of 4-3.
On December 6, 1991 McReynolds along with two other players were traded to the Kansas City Royals. During his two years with the Royals McReynolds hit a combined batting average of .246, hit 24 home runs and 91 RBIs.
On January 5, 1994 McReynolds was traded back to the Mets for Vince Coleman after Coleman started a controversy in New York. McReynolds played his last year of baseball for the Mets, hitting .256 with 4 home runs and 21 RBIs. On October 25, 1994 McReynolds was granted free agency and ended his 12-year baseball career.
McReynolds married his wife Jackie McReynolds in 1987 and had two daughters together. McReynolds is an avid duck-hunter and fisherman. After retiring McReynolds built the Kevin McReynolds Sports Complex near Sylvan Hills High School. McReynolds also runs a commercial duck-hunting club in southeast Arkansas.Inductee, SEC Baseball Legends (2012, inaugural class)
Inductee, National High School Hall of Fame (2011)
Inductee, Arkansas Sports Hall of Fame (1996)
National League Player of the Month (September 1988)
Major League Baseball record for most steals in a season (21) without being caught (1988)
Pacific Coast League MVP (1983)
Bill Dickey Award (1980)
National Baseball Congress World Series MVP Fairbanks (AK) Goldpanners (1980)
NCAA College World Series All-Tournament Team (1979)
Arkansas High School Baseball Player of the Year (1978)
Arkansas Class AAA State Baseball Championship / Tournament MVP (1978)