[3] The village of Glenshaw, Pennsylvania—at the center of what became Shaler Township—was established in the early 19th century, beginning with a log sawmill built by John Shaw, Sr. after he bought 600 acres (2.4 km2) of land north of Pittsburgh in 1800.

Members of the Shaw family subsequently built a log gristmill, a sickle factory, and a coal mine.

[5] While the township was initially confirmed with the name Marion; on the same day the name was changed to Shaler, after Charles Shaler, a prominent mid-19th century Pittsburgh area judge, who served as President Judge of the 5th District Court in Beaver County.

[6] The township is not named for the numerous deposits of shale rock found within its borders; this is instead a common misconception.

Early settlement of the Shaler area was sporadic, with small farming and mercantile villages appearing.

[4] In the late 19th century, the creation of the Glenshaw Glass plant sped up settlement to a certain degree, drawing workers to settle in the vicinity.

Following the Second World War Shaler became an affluent suburb with many former City of Pittsburgh residents now populating the Township.

Shaler, along with Ross Township, was among the first outer-city areas to develop into the modern suburbs which today define the North Hills region of Allegheny County.

Shaler also runs catty-corner (without a direct border) with McCandless Township to the northwest.

Across the Allegheny River to the south, Shaler runs adjacent with the Pittsburgh neighborhoods of Central and Upper Lawrenceville.