The West St. Louis County Jaycees were founded as the Ballwin Jaycees in 1960. The current chapter serves the areas of Ballwin, Chesterfield, Clarkson Valley, Ellisville, Manchester, Town & Country, Wildwood, Winchester and surrounding cities.

The chapter has provided many examples of community and Jaycee leadership; several city officials from Ellisville, Ballwin and Manchester are former or current West County members. Also, the West St. Louis County Jaycees have provided several State Vice Presidents and three State Presidents to the Missouri Jaycees, and one National Vice President to the United States Junior Chamber of Commerce.

Across the city and state, the chapter is known as The Green Machine, a nickname built around the chapter's color, and a name the members are proud to have.