This Morningside Avenue was originally the extension of College Street or Grenadier Road[1] from Parkside Drive but cancelled as High Park was developed.

The foot of Morningside is located at Guildwood Parkway on the shores of Lake Ontario, and traces the original Scarborough Township Lot 10 line north-east toward the commercial centre of the West Hill neighbourhood at Kingston Road.

[2][3][failed verification] Beyond the valley, which was the former northern terminus, the present route was named "Littles Road" after an early family in the area.

The route veers to the north-west north of Sheppard Avenue, skirting the ravine of Morningside Creek and Rouge Park.

[4][5] The low 3.7 m (12.1 ft), narrow, one-lane railroad underpass at Finch Avenue, dating back to when it was a rural road, was replaced in 2009, allowing 4 lanes of traffic to pass below uninterrupted.