The Rosedales were organized as a Winnipeg Junior team to play out of the city’s west end in 1945 and found immediate success in the newly-formed Greater Winnipeg Junior Baseball League. Between 1945 and 1950 the Junior Rosedales won the GWJBL four times and were finalists the other two seasons under coaches Terry and Jack Hind.

A juvenile team was formed in 1946 and won championships in 1946, 1948 and 1950. The Juveniles won 25 of 27 games in their first season, including a 20-game winning streak. The Rosedales added a Midget team starting in 1947 and fielded a Bantam team from 1948-1950.

Unfortunately declining attendance and lack of a suitable diamond forced the organization to fold after the 1950 season, but they went out on top as all three classifications (midget, juvenile and junior) won city titles in 1950. The quality of the teams they put on the field during this era can be attested to by the number of former Rosedales players who have already been inducted into the Baseball Hall of Fame as individuals or as members of other teams.