Composed of portions of St. Clair and Jefferson townships in 1845, South Park was originally called Snowden Township, named after John M. Snowden, a prominent businessman, politician and former Pittsburgh mayor, who had died earlier that year. In the 1930s, Allegheny County acquired several large parcels of farm land mostly within Snowden Township and created a regional recreational area named South Park. The huge success of South Park, and the fact the facility occupies roughly one-third of the community's total area, eventually prompted a 1966 referendum in which the township was renamed.

The area in and around South Park Township was settled in the mid-18th century. It is the location of the Oliver Miller Homestead where in 1794, the first shots of the Whiskey Rebellion were fired. A log house was originally built on the site in 1772; it was replaced by a stone structure around 1830, which is open for public tours.

South Park Township has five borders, including Baldwin to the north, Pleasant Hills and Jefferson Hills to the east, Union Township (in Washington County) to the south, and Bethel Park to the west.

The South Park School District is coterminous with the township. The school district has a single elementary school for grades K-4, a single middle school for grades 5–8, and a single high school for grades 9–12. The school district's mascot is the Eagles.