Lezak s a four-time Olympic gold medalist. He formerly swam for Irvine Novaquatics. He graduated from Irvine High School in 1994, and then from the University of California, Santa Barbara in 1999. He is a member of the Rose Bowl Aquatics swim club.

Lezak was a specialist in the 50-meter and 100-meter freestyle races. He also held long-course world records in the 400m freestyle and medley relays, and is a former American record holder in the 100-meter freestyle.