Both 25, the pair will be at the club for a further two seasons, until the end of 2018, their re-signings following on from recent contract extensions for Lachlan Coote, Antonio Winterstein and Kane Linnett.
"It's a huge boost to be able to sign both those guys, (who are) probably just about coming into the prime of their careers,” said coach Paul Green of the signings. “It’s really good news for the club."
O'Neill is in his second season with the Cowboys and has found a home at right centre, scoring 20 tries in his 40 matches for North Queensland.
