Shadley was born in Winter Park, Florida to Shari and Rick Shadley, a landscape architect. He has an older sister. Shadley's first acting role was in a play of A Christmas Carol in which he played Tiny Tim. From then, his acting career began and he has appeared in Dirty Sexy Money as Brian Darling, Jr. and in the 2009 Jackie Chan film The Spy Next Door. He also voices Gorgonzola in the cartoon series Chowder. He appeared in How I Met Your Mother Season 6 Episode 19 (Legendaddy) as Barney's half-brother, as well as episode 21 in the same role. Shadley was also in season 5 episode 21 of the Ghost Whisperer.