Smith played nine years in the National Football League (NFL) with the Baltimore Colts (1967–1971), Oakland Raiders (1973–1974) and Houston Oilers (1975–1976). The first selection of the 1967 NFL Draft, he was the Colts' starting left defensive end for five seasons who played in Super Bowls III and V, the latter with the winning side. He was named to two Pro Bowls and was a First-Team All-Pro in 1971. Despite being 6 feet 7 inches (2.01 meters) tall and weighing 265 pounds (120.20 kilograms), he had tremendous speed. This combination usually caused him to draw two blockers.
During his acting career, he mainly specialized in comedic roles in films, television advertisements and programs. For about a decade following his retirement from football, he appeared in various commercials for Miller Lite. His best-known role was as Moses Hightower in the first six Police Academy movies.
Posthumously, Smith was diagnosed to have suffered from CTE, a neurological condition generally related to concussion and sub-concussive head trauma.
Smith was born on February 28, 1945 in Orange, Texas to Willie Ray Smith Sr. and Georgia Oreatha Curl Smith, and was raised in nearby Beaumont. His father, Willie Ray Smith, Sr., was a football coach who accumulated 235 victories in a career spent at three high schools in the Beaumont area. Smith had the opportunity to play for his father at Charlton-Pollard High School in Beaumont. The younger Smith developed into one of the state's best-ever high school football players.
Smith originally had hopes of playing college football at the University of Texas. Even though Longhorns head coach Darrell Royal was willing to offer him an athletic scholarship, he was prohibited from doing so because of the prevalent racial segregation throughout the Southern United States. At the time, Texas was a member of the Southwest Conference (SWC), which finally integrated in 1967. The university's football program did not do likewise until three years later in 1970. The situation motivated Smith to become a much better player.
Smith played college football at Michigan State University. He was awarded with All-America honors in 1965 and 1966. Smith was a popular athlete at Michigan State, with the popular fan chant of "Kill, Bubba, Kill."
His final game at Michigan State was a 10–10 tie with Notre Dame at Spartan Stadium on November 19, 1966. It was hyped as "The Game of the Century" because both teams were undefeated, untied and ranked atop the national polls entering the contest (Notre Dame was #1 at 8–0–0, Michigan State #2 at 9–0–0). Early in the first quarter, Smith tackled Fighting Irish starting quarterback Terry Hanratty, who suffered a separated left shoulder on the play. Hanratty was replaced for the remainder of the match by Coley O'Brien. Smith, who admitted that Hanratty's injury actually backfired on the Spartans, stated, "That didn't help us any. It just let them put in that O'Brien who's slippery and faster and gave us more trouble. The other guy just sits there and waits, and that's what we wanted." Michigan State finished second behind Notre Dame in the final voting for the national championship.
In 1988, Smith was enshrined in the College Football Hall of Fame. Michigan State retired his number 95 jersey on September 23, 2006, prior to the Spartans' home game against Notre Dame, amid repeated cheers of his old slogan from the student section. This game also celebrated the 40th anniversary of the "Game of the Century."
Smith spent nine seasons in the NFL as a defensive end. He was the first overall selection in the 1967 NFL draft, chosen by the Baltimore Colts (the pick was originally held by the expansion New Orleans Saints, but the Saints traded the pick to Baltimore in exchange for quarterback Gary Cuozzo). The Colts won Super Bowl V at the end of the 1970 season, earning Smith his only Super Bowl ring. However, in interviews, Smith stated that he would never wear the ring, out of a sense of disappointment that he and his teammates were unable to win Super Bowl III. He was injured in the 1972 preseason when he ran into a solid steel pole the NFL was using at the time to mark yardage and missed the season. He was traded to the Oakland Raiders after the 1972 season, and finished his career with the Houston Oilers. He was selected All-Pro one year, All-Conference two years, and went to two Pro Bowls.
After retiring from professional football, Smith began his acting career in small movie and television roles in the late 1970s and early 1980s. He is perhaps best known for his role as Moses Hightower in the Police Academy movie series, a role he reprised in all but one of the Police Academy sequels. Smith appeared in the 1982 TV film Fighting Back: The Rocky Bleier Story. He was Arnold the driver in the 1983 movie Stroker Ace that cast stars such as Burt Reynolds, Ned Beatty, Jim Nabors, and Loni Anderson. He was a supporting character in the 1981–82 flop Open All Night. He appeared in the episode "All Night Security Dude" of the hit television series Married... with Children as the character "Spare Tire" Dixon and in "Dud Bowl" (season 09, episode 10) as himself. He was the longtime spokesman of Baltimore-area law firm Cohen, Snyder, Eisenberg & Katzenberg. Smith starred in the short-lived television series Blue Thunder, partnering with Pro Football Hall of Fame defensive star Dick Butkus, with whom he frequently costarred in advertisements for Miller Lite beer, as well as their joint cameo in Gremlins 2: The New Batch (1990). Smith also appeared in Tales of the Gold Monkey, in the episode called "God Save the Queen", along with fellow actor James Avery. He appeared as himself in the first episode of the game show Break the Bank, where he taught two contestants ballet for a chance at a trip to Aruba. He appeared on Good Times as Claude, a bodyguard/thug working for Marion "Sweet Daddy" Williams. He also appeared on an episode of The Odd Couple; when asked by Oscar Madison what his most embarrassing moment was, he replied, "When my mother named me 'Bubba'". Smith appeared in the 1982 Taxi episode "Tony's Comeback" (season 4, episode 19) as a football player trying to get back into the NFL after being cut, who inspires Tony (played by Tony Danza) to earn back his boxing license. Smith also appeared on MacGyver (Season 7, Episode 10). Smith also played a character named "Bones" in the October 22, 1993 episode of Family Matters where he played an enforcer to get his boss's money from Eddie Winslow. At the end he teams up with Steve Urkel to play the accordion.
Smith's younger brother Tody Smith played for the University of Southern California and for the Dallas Cowboys, Houston Oilers and Buffalo Bills
Smith was found dead in his Los Angeles home by his caretaker on August 3, 2011. He died from acute drug intoxication and heart disease. Phentermine, a weight-loss drug, was found in his system. His heart weighed more than twice that of an average human heart. He was 66 years old.
On May 24, 2016, it was announced that Smith had suffered from the brain disease chronic traumatic encephalopathy (CTE), a neurodegenerative illness afflicting unknown numbers of former athletes in contact sports. The findings were confirmed by researchers affiliated with the Department of Veterans Affairs, Boston University and the Concussion Legacy Foundation, and released with the permission of the executor of Smith's estate.
Smith is the 90th former N.F.L. player found to have had CTE by the researchers at the Boston University brain bank; they have examined 94 former pro players. According to the Concussion Legacy Foundation, On a scale of 1 to 4 used by the neuropathologist who examined Smith's brain, Smith had Stage 3 CTE, with symptoms including cognitive impairment and problems with judgment and planning.