The South Park Conservatory Theatre (SPCT) grew out of the South Park Summer Theatre, a community group that produced one show each summer between 1974 and 1976. Performances were held at the South Park High School auditorium. South Park High School drama teacher Shirley Custer and her former student Ronald A. Wisniski expanded this program by co-founding the SPCT in 1977. Under Custer's direction, this nonprofit corporation sought to promote the theatre arts among the area's adults and children, as well as to provide educational opportunities through workshops and an apprentice program for high school students.
The SPCT moved its productions to the South Park Fairgrounds, performing on average four main stage shows per season in the Frank Curto Horticultural Building as well as two or three children's theatre shows at the adjacent outdoor natural stage. Due to its interest in providing a wide range of performance opportunities, the SPCT sometimes hosted productions by other local theatre companies including Iron Clad Agreement, Two Star Productions, and Jackie Nicoll Productions. After Custer's death in February 1995, the role of executive director passed to local actress Audrey Castracane and the organization's name was changed to the South Park Theatre for legal and tax purposes.