Eddie Cass was known to his many admirers as "Mr. Baseball". Cass played and promoted the sport with distinction throughout a long and illustrious career. Upon completion of secondary school, Cass took the baseball skills learned from his father and entered Georgetown University in Washington, where he earned his first degree in 1916 and was a member of the baseball team. Cass served with the American military during the Great War and returned to Winnipeg in 1919 where he enrolled in the Faculty of Law at the University of Manitoba and again played baseball.

From 1919-1926, Cass was a first baseman for the Catholic Club and famous Columbus teams and was a regular all-star. While still a player, Cass coached his Columbus teams to Provincial Championships at the Junior level in 1923 and the Intermediate level from 1924-1926. After he was called to the Bar in 1926, Cass' playing days were over but his name was synonymous with the Columbus Junior teams that continued to win provincial titles well into the 1950s.

Cass was involved many other sports in Manitoba. In 1931, Cass and Shorty Kennedy established the Winnipeg High School Football League while his collaboration with Sydney Halter resulted in the annual Catholic Field Day at Sargent Park which took place for decades. Cass participated in many charitable activities for the Children's Aid Society, St. Joseph's Hospital, Misericordia Hospital, St. Paul's College, the Community Chest, and particularly his work on behalf of the mentally handicapped. A renowned orator, Cass' speeches inspired many Manitobans throughout the years and he has remained much respected as a humanitarian and sportsman.