Between 1940 and 1950, the Mt. Greenwood community's population nearly tripled as industrial growth in the city's southwest side and south suburbs drew workers to the area. The Bureau of Parks and Recreation responded with efforts to create a small park. In 1952, the bureau acquired 1.8 acres, transforming the site into what was originally known as Sawyer Playground. Six years later, the city renamed the park in tribute to David T. McKiernan (1902--1957), who had recently died. McKiernan was in his second term as 19th ward alderman, after having served for sixteen years as an aid to John J. Duffy, the ward's previous alderman. In 1959, the city transferred ownership of McKiernan Park to the Chicago Park District, along with more than 250 other properties. By the early 1960s, the park included a small recreation building, a playfield, playground equipment, a sand box, basketball and volley ball courts, and a spraypool. The park district undertook a major improvement of McKiernan Park's landscape in 1972, and installed a new soft surface playground in 1988.

Located in the Mt Greenwood Park neighborhood, McKiernan Park totals 2.18 acres and features a multi-purpose clubroom. Outside, the park offers two baseball diamonds and a playground.

Park-goers can participate in preschool activities, T-Ball, soccer, Moms, Pops, & Tots, and tumbling. On the cultural side, McKiernan Park offers dance, tap and ballet. During the summer, youth can participate in the Chicago Park District’s popular six-week day camp.

In addition to programs, McKiernan Park hosts fun special events throughout the year for the entire family such as holiday-themed events.