Called the White Tatum by jazz great Art Tatum. He was the musical director for Mister Rogers' Neighborhood until his 1996 death.
He was a graduate of Carnegie Mellon University with degrees in music and education.
His death was often mistakenly reported to be from leukemia, but it was actually caused by anemia.
He was married to Helen Costa from 1941 until his death in 1996. They had two kids named Debbie Elwood and John Costa, Jr.
His partnership with Mister Rogers' Neighborhood creator and host Fred Rogers was lengthy. Rogers thought him to be among the world's most talented musicians.