He guest starred as Danny (The Yeti) in Friends and had a recurring role as Julia's son Payne in Designing Women.

[1] He began his acting career at the Arkansas Arts Center in Little Rock, in the role of the younger brother in Life with Father, based on Clarence S. Day Jr.'s autobiographical novels.

Newbern's first lead role was in 1987's Double Switch, a retelling of The Prince and the Pauper that aired as a part of the Wonderful World of Disney television series.

He has since guest-starred on television in such series as Providence, Chicago Hope, Friends, Bull, CSI, Medium, Ghost Whisperer, Touched by an Angel, Criminal Minds, and Private Practice.

On February 26, 2016, the DC Universe Online Facebook page reported that Newbern would be taking over the role of Superman from Adam Baldwin.

Newbern also lent his voice in the cartoon series The Pirates of Dark Water, and he has also done voiceovers on a number of video games and game-related productions.