I had heard another version of how B.B. got his nickname -- the story goes like this.
In 1948, B.B. got his first break when he had the opportunity to perform on Sonny Boy Williamson’s radio program. It aired on KWEM in West Memphis. This led to B.B. having a ten-minute spot on WDIA. It became known as “King’s Spot”. It was so popular that it expanded and became the “Sepia Swing Club”. B.B. was becoming very popular and knew that he needed a catchy name.
He started out as “Beale Street Blues Boy”. That name was shortened to “Blues Boy King”. Then, from that, came “B.B. King”.
I guess there are lots of rumors about his name though -- does anybody know if B.B. himself ever said how he got his name?