Begun in 1955 and completed in 1966, the expressway was one of the first projects undertaken by the newly formed government of Metropolitan Toronto. It is named for the first chair of Metro Council, Fred Gardiner, who championed the project. Originally it ran along the Lake Ontario waterfront from west of the Humber River, where it joined the Queen Elizabeth Way, to Leslie Street, about 2 km east of the Don Valley Parkway (DVP).
The stretch east of the DVP was part of a planned extension through the eastern suburb of Scarborough, meeting up with Highway 401. The central portion of the Scarborough Expressway was never completed.
Subsequent to the 1998 amalgamation of the Metro municipalities into a single government, the stretch of the Queen Elizabeth Way between Highway 427 and the Humber River became part of the Gardiner. In 2001 the Gardiner's short eastern spur was demolished, as the level of traffic it carried was considered too low to justify the high maintenance costs of the elevated roadway.
As one of the few express routes for motor traffic into the downtown core, the Gardiner is regarded by many as essential to the city's economy, but its presence remains one of the most contentious urban planning issues in Toronto. Critics of the expressway have long decried its appearance and argued that it cuts off the city from its waterfront. In recent decades several proposals have been made to dismantle it or replace its central section with a tunnel. The most recent and detailed of these proposals was part of a wide-ranging report presented by the Toronto Waterfront Revitalization Task Force in 1999. Lack of municipal funds and political will has repeatedly stalled such plans.
During the demolition of the Gardiner East, several of the concrete pillars that once supported the roadway near Leslie Street were left standing, and incorporated into a public art project as a commemoration of the era in which they were constructed.
See also: Spadina Expressway