Michael Bruner grew up in Stockton, California and qualified for his first AAU National Championships at age 14. Following graduation from Lincoln HS, he moved to Cupertino to train with the De Anza Swim Club. He competed in the 1976 Olympics in two events: the 200-meter butterfly and the 800 meter freestyle relay – earning a gold medal in each in record times. He went on to attend Stanford University and competed for the Cardinal, graduating in 1979.

In 1980, Bruner was the high point winner at the Indoor U.S. National Championships and the U.S. Olympic Trials. However, he did not compete that year due to the Olympic boycott of the Soviet Games. He was, however, awarded the 1980 American Swimmer of the Year, and in 1988 he was inducted into the International Swimming Hall of Fame.

Bruner joined the San Jose Sports Hall of Fame in 2016. His SJSHOF plaque is located at SAP Center outside of Sec. 112.