Smith was one of the best sprinters in the world in the 1980s, though for most of his career Smith, who was a quiet and unassuming character, ran in the shadow of the more charismatic American sprinter Carl Lewis.
At the inaugural Athletics World Championships in 1983, Smith claimed Gold Medals in the 200 m and the 4 x 100 m relay (which the US won in World Record time), as well as a Silver Medal behind Lewis in the 100 m.
At the 1984 Summer Olympics in Los Angeles, Smith won a gold Medal as part of the US 4 x 100 m relay team, again establishing a new World Record in this event.
At the 1987 World Championships, Smith successfully defended his 200 m Gold. (At that time, the World Championships were held once every four years, whereas presently they are held every two years.)
At the 1988 Summer Olympics in Seoul, Smith was involved in the most controversial Olympic 100 m final of all time and ended up receiving the Bronze Medal. Ben Johnson of Canada crossed the line first, with Lewis second, Linford Christie of Great Britain third, and Smith fourth. When Johnson tested positive for anabolic steroids and was stripped of his Gold Medal, Smith was upgraded to the Bronze Medal position. The race has been called by one newspaper "the dirtiest race in history", as Lewis later admitted to having tested positive for stimulants in that year's trials, and Christie's urine also contained metabolites of a banned substance after the race. Of the top 5 in that race, Smith is the only one who never failed a drugs test. Smith later said: "I should have been the gold medallist". In the ESPN documentary 9.79*, eventual silver medallist Christie states, and footage of the race shows, that Lewis "ran out of his lane... two or three times" during the race, which should have resulted in Lewis' automatic disqualification. This should have elevated Smith to, at least, the silver medal.
Smith missed out on what seemed like a likely Gold Medal in the 4 x 100 m relay in Seoul because the US did not reach the final following a disqualification for passing the baton outside the legal area.
Smith continued to run for the US into the 1990s. In the later years of his career, he was named captain of the US athletics team at major events including the Olympic Games and World Championships.
His son, Calvin Smith Jr., runs the 200, 300, and 400 for the University of Florida. He’s “earned 16 All-America titles - the most in UF track and field history - plus one national championship...” and was an alternate "in the 2008 Beijing Olympic Games on the U.S. 4x400 relay.”