Desjardins moved as a young boy with his family from Canada to Miami Beach, where he grew up. At the age of 13, he began with water jumping. As a U.S. citizen he could then for the Olympic Summer Games in 1924 qualify in Paris, winning a bronze medal in springboard diving from 3 m. In diving it simply binned on the 6th Place.
Four years later at the Summer Olympics in Amsterdam, he won the gold medal in both the diving and in springboard diving. The result in the diving was controversial. Farid Simaika, an Egyptian who studied at UCLA, scored the higher score and was first declared the winner. The victory ceremony was already underway and the Egyptian national anthem was being played, as the judges changed their decision. Since four of the five judges Desjardins binned before the Egyptians, the gold medal was given to the Americans by the applicable rules.
After the Games in 1928, Desjardins has been declared as a professional because he participated with Johnny Weissmuller, Martha Norelius and Helen Meany on swimming performances. Formally, he moved in 1931 to professional sports and gave many demonstrations continue.
Desjardins studied from 1927 economics at Stanford University and was inducted into the Stanford Athletic Hall of Fame, though he could never win a high school championship. This was mainly because the Amateur Athletic Union in 1929 suspended him because he took too many cost contributions for demonstrations. However, he could win a total of 13 AAU titles.
In 1966, Desjardins was inducted into the International Swimming Hall of Fame in Fort Lauderdale.