Co-written and first recorded by Johnny Moore’s Three Blazers (R&B #3 1947).
Other popular versions by Chuck Berry (1958); Elvis Presley (1971); Bruce Springsteen (1987); Bonnie Raitt & Charles Brown (1992); Cee Lo Green, Rod Stewart & Trombone Shorty (2012).
From the wiki: “‘Merry Christmas Baby’ is an R&B Christmas standard written by Lou Baxter and Johnny Moore. The original 1947 version by Johnny Moore’s Three Blazers is considered to be the definitive version of this song.