The former Warriors and Canberra NRL front-rower has reportedly given the game away following a short-lived stint with UK Super League side Widnes.
The 28-year-old headed to England last year after gaining a mid-season release from the Raiders, but made just four appearances for Widnes before being released following the club's relegation.
"He has left rugby league and he is doing a teaching job in Wellington," Gubb's long-time manager and former Kiwis coach Frank Endacott told Foxsports.com.au.
"I doubt he would come back to the game unless there was an offer which was good enough, and I think he's pretty disillusioned."
After parting ways with Widnes, Gubb was poised to sign a new contract with the London Broncos but the deal never materialised.
Rather than try to find another new club either in the Super League or NRL, Wellington-born Gubb has returned to his home town and taken up a new career path.
Endacott is adamant his client still has plenty to offer rugby league and is disappointed circumstances have seen him give the game away.
"I know the scene in England pretty well and he was ready to sign with the London Broncos," he said.
"He would have been one of their top line players and I offered them Charlie on a plate, but then they chose to stick loyal with the players that had got them promoted.
"Good luck to them. He would have been perfect for London and after all that, Charlie got pretty disillusioned with it all.
"He is at the perfect age, his fitness is really good and everywhere he goes he becomes a crowd favourite. His teammates love playing with him because he is tough and plays on the fine line.
"He's too good a player not to be playing, and you can only get so many knock backs before you give up. It is a great shame that he has chosen to have a spell out of the game."
A Warriors junior, Gubb was a member of the club's 2010 under 20s grand final winning side that also contained Kiwis test star Shaun Johnson.
He was released by the Warriors soon after and made the move across the Tasman where he spent two years honing his craft with the Wynnum Manly Seagulls in the Queensland Cup.
The Warriors eventually re-signed him and he made his first grade debut in 2013, before going on to make 39 appearances for the Auckland-based outfit.
Gubb's fearless style of play earned him cult status among the Mt Smart faithful but the NRL made an example of him in 2016 when they handed him a seven week suspension for a shoulder charge on Manly's Darcy Lussick.
He was disappointed the Warriors did not offer him a contract extension beyond 2017 and reluctantly left to join Canberra where a serious groin injury contributed to him making just five appearances in the lime green.
