This film originally aired in 1960 on CBS Television as part of its "Ford Presents" series.
The entire film in high quality (of which this clip is a small part) was painstakingly hunted down by YouTuber erp65 and his friends. It can be found here, and I urge you, I really DO urge you, to see it in its entirety.
Glenn Gould's U.S. Television Debut: Bernstein Conducting Bach's Keyboard Concerto No. 1 in D minor