Smith played three years of college football for the Florida Gators, where he set numerous school rushing records.

He is also one of four running backs to lead the NFL in rushing three or more consecutive seasons, joining Steve Van Buren, Jim Brown, and Earl Campbell.

While playing for Dallas, Smith plus quarterback Troy Aikman and wide receiver Michael Irvin were known as "The Triplets," and led their team to three Super Bowl wins during the 1990s.

[9] For his efforts, Smith was named the 1986 national high school player of the year by several publications and organizations, including USA Today, Parade Magazine, and Gatorade.

"[13][14] Smith accepted an athletic scholarship to attend the University of Florida in Gainesville, where he played for coach Galen Hall's Gators for three seasons (1987–1989).

[15] He did not start the first two games of his college career in the fall of 1987, but made the most of his opportunities in a second-week rout of Tulsa in which he gained 109 yards on just ten carries, including a 66-yard touchdown run.

[16] That performance earned him a spot in the starting lineup the following week in the Gators' SEC opener against Alabama at Legion Field.

In his first collegiate start, Smith promptly broke Florida's 57-year-old all-time single game rushing record held by Red Bethea, carrying 39 times for 224 yards and two touchdowns as the Gators upset the Crimson Tide.

However, during the sixth contest against Memphis State in mid-October, he was sidelined with a sprained knee while starting quarterback Kyle Morris broke his finger, leading to an upset loss.

[21] Smith was unable to return to action for a month, during which Florida lost four games in a row and did not score a touchdown in 14 consecutive quarters of play, including a 16–0 loss to Auburn that is their most recent shutout to date.

[31] Smith, concerned about his potential role in Spurrier's reportedly pass-first offense, decided to forgo his senior year at Florida and enter the NFL draft, which for the first time in history allowed juniors to be eligible.

[35] In the 1990 NFL draft, the Dallas Cowboys considered drafting linebacker James Francis with their first round selection, but after he was taken by the Cincinnati Bengals, the Cowboys focused on improving their running game when Smith started dropping, because despite his collegiate success, some NFL teams still felt that Smith was too small and slow for the pro game.

With the season in jeopardy the Cowboys relented and reached an agreement, making Smith the highest paid running back in the league.

His career signature game came in the season finale against the New York Giants, with the Cowboys desperately trying to clinch the NFC East title and a first-round bye in the playoffs, Smith suffered a first-degree separation in his right shoulder during the first half, but still finished with 229 total yards and played a key role in a 16–13 overtime win.

[48] In 2002, he reached the goal he set as a rookie, finishing the season with 17,162 career yards and breaking the NFL rushing record previously held by Walter Payton against the Seattle Seahawks.

[54] After the season, the Cowboys hired head coach Bill Parcells who wanted to go with younger running backs and released Smith on February 26, 2003.

[58] On October 5, in a highly anticipated game, he returned to Texas Stadium to play against the Dallas Cowboys, but suffered a broken left shoulder blade after safety Roy Williams hit him in the second quarter.

[68] He was not re-signed by the Cardinals and signed a one-day contract for one dollar with the Dallas Cowboys, after which he immediately retired with the team he had played with for most of his career.

His 1,586 yards rushing is also top on the NFL postseason chart, and he shares the total playoff touchdown mark of 21 with Thurman Thomas.

"[16] Smith was noted for being a very durable back with excellent vision, tremendous leg strength, and great balance, and was known as one of the best second-effort runners ever.

[79] During his career, he was often compared to Detroit Lions Hall of Fame running back Barry Sanders, as both men were extremely successful for their respective teams and combined for eight rushing titles during the 1990s.

On September 19, 2005, at halftime of the Cowboys-Redskins game (broadcast on Monday Night Football), Smith was inducted into the Dallas Cowboys Ring of Honor with his long-time teammates Troy Aikman and Michael Irvin.

Sports Illustrated's Peter King called Smith's comments regarding Michael Vick's involvement in the Bad Newz Kennels "idiotic and inappropriate.

[91] On February 7, 2010, Smith flipped the coin at the start of Super Bowl XLIV between the Indianapolis Colts and New Orleans Saints.

In 2005, Smith made his first move toward becoming a real estate developer: He teamed with another Cowboy legend, Roger Staubach, the founder and CEO of Staubach Co., to form Smith/Cypress Partners LP, a real estate development enterprise specializing in transforming underutilized parcels in densely populated areas into commercially viable properties anchored by national retail giants.

[93] In his first deal, Smith helped the firm sign Mervyn's, a California-based department store chain, to anchor a $45 million, 230,000-square-foot (21,000 m2) project in Phoenix.

On one of the sites, Smith plans to build a complex with as much as 600,000 square feet (56,000 m2) of retail space, more than double the size of the Phoenix property.

][citation needed] Smith/Cypress is a joint venture (Smith owns 51 percent) with Cypress Equities, the retail development arm of Roger Staubach's real estate services company.

[95] Smith also co-founded ESmith Legacy, a Baltimore-based company that specializes in commercial real estate development and investment management.

In 2016, Smith took the position of co-owner alongside founder and president Ben Davis of The Gents Place, an ultra-premium men's grooming and lifestyle club founded in Frisco, Texas.