Without any major commercial, industrial or entertainment destinations, the station primarily serves the residents of South Rosedale, from which it is within walking distance, and St. James Town and Cabbagetown by way of the 65 Parliament and 94 Wellesley bus routes.

The station was rated as high priority in the requirement for a second exit[2] which, although scheduled to be finished by January 2010,[3] finally opened in December 2012 after many delays.

[4] This project still did not make the station accessible, although the stairs give subway riders a direct connection to the bus bays.

Late in the fourth quarter of 2021, construction started to install two elevators to make Castle Frank station accessible, connecting the street-level concourse to each of the east- and westbound platforms.

Its streets, and the brook that flows through it, are in turn named after John Graves Simcoe's summer residence in the area overlooking the Don River, which burned down in 1829.