Mike Troy began his competitive swimming career in the Indianapolis park district program, but joined the Indianapolis AC before enrolling at Indiana University. At the 1959 Pan American Games, he finished second to Dave Gillanders in the 200m butterfly but gained his revenge at the 1960 Olympics, where Troy took the gold medal and Gillanders placed third. At both the 1959 PanAm Games (with Frank McKinney, Jeff Farrell, and the non-Olympian Kenneth Nakasone) and the 1960 Olympics, Troy was a member of the winning freestyle relay team.
Troy was a prolific record breaker in butterfly, setting six world records in the 200 fly in 1959-60. He also swam on two world record setting 4x200 free relay teams and one world record medley relay team. He also won the AAU 100 fly in 1958 and the 200 fly in 1959-60. At the NCAA Meet, he won the 100 and 200 fly in 1960, also swimming butterfly on the winning Indiana University medley relay team. As an officer, Mike Troy was decorated for valor while serving with the Navy in Vietnam, earning a Silver Star. He later became involved in real estate brokerage in California, before moving to Arizona later in life where he also coached swimming.