Built in 1929, the Trinity Presbyterian Church/Happy Workers Day Care is important for its association with St. Petersburg's educational, social and religious history. The two establishments jointly used the property until 1968, when the Presbyterian congregation relocated to 22^nd Avenue South. It is one of the few sites within the African-American community that currently maintains its original historic use.

In 1928, the Presbyterian Synod of Atlanta determined this section of south St. Petersburg should have a church and chose Rev. Oscar M. McAdams as ordained minster. Born in South Carlolina in 1887, McAdams was a graduate of Johnson C. Smith University in Charlotte, N.C. and the Auburn, N.Y. Theological Seminary. He also spoke five languages and taught mathematics at 16th Street Middle School and Gibbs High School. In addition, he served as President of the Interdenominational Ministerial Alliance and President of the St. Petersburg Branch of the NAACP, and commissioner to the General Assembly of the Presbyterian Church USA. McAdams. His wife, Willie Lee, first established the church in a wood frame Vernacular-style building believed to have been constructed as a private residence in 1928. It was altered slightly in 1929-30 by enclosing the porch and relocating the front portion. In 1929 the McAdams established a Day Nursery at the church. Five children, whose parents paid 25 cents a week, made up the initial Happy Workers Kindergarten. This facility also housed the first "Colored Summer Vacation Bible School of Youth" in St. Petersburg.

In 1943, the Children's Interracial Organization (CIO) was formed to assist the Happy Workers Day Nursery and Kindergarten, helping to raise funds for its operation and expansion. The organization continued to play a key role in the operation of Happy Workers until the early 1970s. In 1966, the CIO held a benefit for the Happy Workers Day Nursery at the Pasadena Community Church. The event was a Freedom Concert by Coretta Scott King (Mrs. Martin Luther King, Jr.) featuring "The Story of the Freedom Movement in Narration, Song and Poetry". (When Happy Workers acquired the property from the church in 1968, it first renamed the building after the slain civil rights leader who was martyred that year.)

The Trinity Presbyterian Church building is a one-story Vernacular style wood frame structure with a stucco exterior. In 1948 the church underwent extensive renovations which brought the building to its present appearance. The designer of the remodeling project was Peter "P.P." Perkins, a local contractor who supervised the construction. The most significant feature of the building is a tower over the entrance at the northwest comer, which has two levels, with the top featuring two vertical windows on each side. Above each window is a decorative crescent-shaped accent. The second level has a single window on each side bordered with a vertical band of glass blocks. Beneath the tower along the north facade is an arched opening which leads to a small entrance foyer with a double-door.