In 1920, the Los Angeles Chamber of Commerce requested that Charles Weeks come to the San Fernando Valley to establish a series of one-acre egg farms. The farms would be based on the successful formula Mr. Weeks developed in East Palo Alto, California. The "poultry colony" Mr. Weeks created in the Winnetka area of the valley eventually developed into a small farming community named Weeks Poultry Colony. Later Weeks renamed the colony to Winnetka, after a farm he owned in Winnetka, Illinois. Before World War II, this area was rural, in agricultural use, as was much of the western San Fernando Valley. Despite a common misconception, the township of Winnetka was never a part of neighboring Canoga Park. Winnetka was founded in 1922 by Charles Weeks and has remained a distinct entity since. Canoga Park did not receive its name until 1931.

Winnetka is also home to several parks and recreation centers. Winnetka Recreation Center has an indoor gymnasium without weights, which can be used as an auditorium; it has a capacity of 400. In addition the center has a lighted baseball diamond, a children's play area, a community room which often hosts election polls, and picnic tables. Quimby Park, which is unstaffed, has unlighted outdoor basketball courts, a children's play area, and unlighted tennis courts. The park has no toilet facilities.

Runnymeade Park is also an unstaffed pocket park, with a children's play area, picnic tables, and unlighted tennis courts. It is also home to Winnetka Child Care Center: operated by the city in Winnetka. The center takes children from ages 3 to 13 and has a capacity of 59 after-school children and 40 preschool children.