Desaulniers played squash for Harvard University, and won the US intercollegiate title in 1977, 1978 and 1980 (he missed the 1979 event because of a broken foot).
Desaulniers is probably best remembered for his win over the legendary player Sharif Khan in the final of the 1982 North American Open (the most prestigious title in hardball squash at the time). Desaulniers' 10-15, 15-12, 15-8, 15-9 win over Khan ended a run of six consecutive titles at the championship for Khan, and marked only the second time that Khan had failed to win the title since 1969. Khan never won the title again.
A series of injuries kept Desaulniers away from the tour in 1983. He made a successful return in 1984, and then retired from the game in 1986.