[2][3] Mann learned to swim at eight in his hometown of Leeds, West Yorkshire, England, at the public bath house.

[4][7] He coached 13 National Collegiate Athletic Association champion swimming teams at the University of Michigan between 1925 and 1954, who also won 16 Western Conference titles.

[4][9] His outstanding male swimmers included 1936 Olympic gold medalist and diver Richard Degener, 1932 freestyle Olympic medalist Jim Cristy, 1936 Olympian and Coach Taylor Drysdale, NCAA Backstroke champion and world record holder Harry Holiday, 1952 Olympians Burwell Jones and backstroke gold medalist John Davies, 1953-55 NCAA freestyle champion Jack Wardrop and brother 1952 backstroke Olympian Bert Wardrop.

His University of Michigan swimmer John Davies took a gold medal, winning the 200-meter men's breaststroke in an Olympic record time of 2:34.4.

Many peers from coaching and friends attended the summer camp and a number of Olympic athletes trained and developed there.

[11] On August 6, 1962, Mann died at Camp Chikopi, which he founded in 1920 in Northern Ontario, Canada near Burk's Falls.

He collapsed in his bathroom after telling his family he felt tired, and several press reports speculated a heart attack as cause of death.

[5] His survivors, several of who continued to operate Camp Chikopi, included his wife Mary Lea, his daughter Mrs. Rosemary Dawson, and his son Matthew Mann III, a U of Michigan swimming star and later coach at Lansing High School.

[12][9] He was a member of the Ann Arbor Rotary Club, the First Church of Christ Scientist, and Phi Kappa Tau Fraternity.