I just came across a Life magazine article about an old jazz alto sax player named Boyce Brown. He converted to Catholicism in 1952, joined the Servite friars in 1953 and became Brother Matthew, was permitted by his superiors to record an album with some old friends in 1956 (for the benefit of the missions), and passed away in 1959.
Brother Matthew in the recording studio. This story goes on for a few pages after, but this is the best pic.
Here’s a long blogpost from a jazz fan, mostly about his career before the monastery. Features some interesting comments on the post, so read all the way down.
You can also buy his Brother Matthew album on Amazon.