Clemmons was born in Birmingham, but his family moved to Youngstown, Ohio when he was a child. He learned to sing negro spirituals form his grandmother and performed at school and church functions, later fronting a rock band. He studied music at Oberlin College and earned a master of fine arts at Carnegie Mellon University. He auditioned successfully for the Metropolitan Opera in Pittsburgh, Pennsylvania and earned a position in the Opera Studio, performing with numerous companies across the country.
Clemmons joined the cast of "Mister Rogers Neighborhood", portraying a police officer and owner of a singing and dance studio. He also continued to perform professionally. His performance as Sportin' Life in the Cleveland Orchestra's recording of "Porgy & Bess" won a Grammy in 1973. In the 1980s he returned to singing spirituals and founded a professional performing company, the Harlem Spiritual Ensemble, which he dedicated to "preserving, sustaining and commissioning new and traditional arrangements of American Negro Spirituals for future generations." Many of Clemmons' real-life achievements were reflected on the program.
In his later career, Clemmons arranged a song-book entitled Song For Today, published by Strube Verlag of Munich, Germany and wrote and produced a musical based on the life of Roland Hayes in 1997.
Clemmons is currently a scholar and artist-in-residence at Middlebury College in Middlebury, Vermont.
- Morris, Jasmyn Belcher (March 11, 2016) "Walking The Beat In Mr. Rogers' Neighborhood, Where A New Day Began Together" NPR.org