Lamont Peterson announced his retirement after losing to Sergey Lipinets on Sunday.
The American, 35, was dropped late in the 10th round at the MGM National Harbor after an action-packed fight between two former champions.
After losing, Peterson confirmed the fight – his 41st – would be the last of his professional career.
"It's been a long career, but today is the day and I thank you for the support throughout my career," he told Fox Sports in an in-ring interview.
"I love you all, I'm always going to support this area, but I'm sure it's time for me to hang it up and I just want to say I appreciate you all, thanks a bunch.
"I couldn't go out a better way, at home, main event and this is going to be the last time you see me in the ring. Thanks for everything."
Peterson (35-5-1) finishes his career as a former WBO and IBF light-welterweight champion.
Lipinets (15-1) landed the decisive blows towards the end of the 10th round, dropping Peterson.