A school statement says Marienthal died from heart problems at age 89 Wednesday.
The Chicago-born Marienthal was 19 when he played for UCLA's first Rose Bowl team, which lost 9-0 to Georgia in 1943.
He left school to fight in World War II, losing his leg and earning a Purple Heart as a Marine at the Battle of Okinawa in 1945.
Marienthal returned to serve on the football team's coaching staff from 1946 to 1948.
And from 1946 to 1996 he worked as official scorer for the Bruins basketball team, documenting all 11 of the school's national titles.