Halsey
Pop singer Halsey has never gone by her real name, Ashley Frangipane, professionally. Halsey is an anagram of her first name and was inspired by a street in Brooklyn. A friend of hers lived on Halsey Street, where she'd spend several weekends away from her Jersey hometown.
Spike Lee
Director Spike Lee was born Shelton Lee, a much less impressive-sounding name. His mother nicknamed him Spike when he was a child because, as he says, he was a "tough baby." It carried over into Hollywood well.