A graduate of Irvin High School, Cancellare swam at Midland College and graduated from the University of Texas at El Paso. He was the head coach of the El Paso Aqua Posse from 1979-1999, and was a dynamic force in West Texas swimming. More than 80 of his swimmers attended college on swimming scholarships, and his coaching produced 79 high school all-Americans and five Olympic team members. He was the principal and president of Cathedral High School. Leo passed away in 1999 at age 41 after a year-long battle with cancer.