Smith was a standout basketball player at Brigham Young University. He excelled in both football and volleyball before concentrating on basketball exclusively. Smith served two years (1984–86) as a Mormon missionary before returning to BYU to finish his collegiate basketball career.
Smith was a first round draft pick of the Boston Celtics in 1989 (13th overall) as a 24-year-old. He played two seasons with the Celtics before being waived in 1991, and spent several years playing overseas in Spain (he speaks fluent Spanish) before returning to the NBA in 1994-95 with the Clippers. (Smith is not to be confused with another American player also named Mike Smith who had a long career in Spain, became a Spanish citizen, and played on the Spanish team).
Smith followed his playing career by becoming a broadcaster, first as a color commentator on BYU's basketball telecasts, and then as a Clippers broadcaster. For the better part of four seasons (1998–2002), Smith worked as the team's radio play-by-play announcer, as well as a fill-in television color commentator alongside legendary Clipper voice Ralph Lawler.
When regular team TV commentator Bill Walton left to work exclusively for ESPN and ABC Sports in 2002, Smith moved over as Lawler's permanent partner on televised and non-televised games. He also served as a coach on the Clippers' Summer League teams on several occasions, and subsequently joined Lakers television announcer Joel Meyers in broadcasting several Toshiba Vegas Summer League games for NBA TV. Smith and Lawler often engage in playful banter during Clipper broadcasts, usually covering subjects such as Smith's frequent time on the bench in Boston. Lawler will also be quick to point out what he believes to be erroneous statements on Smith's part.
On December 26, 2007, Smith and his wife Debbie welcomed their 9th and 10th children into the family, a boy and girl.