He started writing songs and playing the drums at age four and would often perform with his brother, Mike Mahaffey, when they were growing up.

[1] By age eleven, he was playing drums at Dollywood, Dolly Parton's theme park in Pigeon Forge.

Some well-known artists he has worked with include Pink, Beck, Liz Phair, Tenacious D, Lupe Fiasco, Snoop Dogg, Phantom Planet, Beyoncé, Butch Walker, Hellogoodbye, Forever the Sickest Kids, Miranda Cosgrove, The White Tie Affair, Keith Urban, The Sounds, L.E.O.

[5] Mahaffey also contributed to the film score of The Boss Baby: Family Business and was the composer for Rise of the Teenage Mutant Ninja Turtles: The Movie.

Mahaffey also played the Muppet character "Animal" in a drum-off with Blink-182 drummer, Travis Barker, on Jimmy Kimmel Live!.

[5] He provided the Score and Songs for Disney's Henry Hugglemonster, Nickelodeon's Sanjay and Craig, Nella the Princess Knight, Rise of the Teenage Mutant Ninja Turtles, The Barbarian and the Troll.