Mark Henderson was a butterfly and freestyle swimmer who had an extensive medal record internationally in the early 1990s. He won Olympic gold in the medley relay at Atlanta in 1996. At the World Championships he won medley relay golds in 1991 and 1994. In 1993 he won a gold (medley relay) and two silvers (100 fly, 4x100 free relay) at the short-course Worlds. Henderson competed four times at the Pan Pacific Championships, winning four gold medals and seven medals between 1989-95. He also won two golds (100 fly, medley relay) at the 1995 Pan American Games.
Henderson attended U Cal Berkeley. After retiring from swimming, he worked in the financial industry with JP Morgan, Citigroup, and Janney Montgomery Scott. He retired from Wall Street in 2016, to focus on his own endeavors helping young athletes. Henderson was also known for his work with various charities. He was married to US Olympic swim star and television personality Summer Sanders from 1997-2001, although they divorced.