The Toronto Transit Commission operated Bloor streetcar lines from its creation from earlier private systems, in 1921, until the line was replaced by the Bloor-Danforth subway line in the mid-1960s. The first pre-TTC streetcars ran on Bloor in 1890.
The TTC built its first subway to replace its busiest route, the north-south Yonge streetcar line, in the early 1950s. The Bloor-Danforth replacing the TTC's second most popular streetcar line was built during the 1960s. In 1966 the stations from Keele to Woodbine were opened, leaving stubs of the old streetcar line running. Finally the remainder of the line was retired in 1968, when the subway was extended to Islington in the west and Warden in the east.
In 1923 the line was extended as far as Jane Street, near the edge of city boundary. Prior to the city amalgamating all the routes operated by private streetcar companies into the city owned and operated TTC, different companies had operated shorter routes on their own sections of Bloor and Danforth. At one time there were four separate services running on different sections of Bloor. Up until the completion of the Prince Edward viaduct, in 1918, there was a gap between Sherbourne and Broadview Avenue. When service was built connecting Sherbourne and Broadview it was built in a dedicated right of way beside the road, and only moved to the middle of the road when Bloor was widened.
At its Jane and Luttrell Avenue termini the TTC operated the Jane Loop, and the Luttrell Loop, stops shared with bus and trolleybus routes, allowing passengers to transfer to the other vehicles.
After the Yonge subway line was built stairs were built allowing travelers to walk up to a pair of platforms in the middle of Bloor, where they could board eastbound or westbound streetcars.