The 26-year-old has been in hot form to lead the Broncos' mid-season revival on the back of five wins ahead of Friday night's clash with Parramatta at Suncorp Stadium.
Hetherington started the season at lock before coach Michael Maguire switched Pat Carrigan back there from prop in round 14.
The past two games, with State of Origin players out, Hetherington started at lock and prop and was outstanding to prove he has a future as a starting middle.
His manager Chris Haddad told AAP that Hetherington was thriving at the Broncos and had set himself an admirable goal.
"Manly made an offer for three years, but we have signed a one-year deal to see if Kobe can get his starting lock spot back. He will give it a good shot," Haddad said.
"Kobe believes the side can win a grand final this year and next year and he wants to be part of that success."
Haddad said his client was satisfied to accept a one-year deal and keep his options open, even though the Broncos were prepared to extend the length of the contract.
"Kobe loves the Broncos, but you never now what will happen in the future," he said.
Hetherington also received interest from St George Illawarra and Canberra.
The son of former Canterbury premiership-winning hooker Jason Hetherington, Kobe is one of captain Adam Reynolds' favourite players.
Reynolds has likened him to a cattle dog because "he has a bit of mongrel and fight in him like a cattle dog and just keeps going".
The genesis of his prowess was in a cattle-yard in rural central Queensland.
"When Kobe and his twin Zac were five years old I would get them to tackle calves," Jason Hetherington told AAP recently.
"I'd be doing all the cattle work and with the calves that I'd brand and let through I'd say, 'go and tackle them boys, wrangle them, jump on them and ride them'. They would get in there and bulldog them and scruff them."
Kobe was recruited by shrewd Broncos recruitment chief Simon Scanlan.
"The Broncos signed him from a schoolboy game in Rockhampton when Simon Scanlan spotted him and his brother Zac," Haddad said.
"Canterbury came in with interest, and Jason sent Zac to Canterbury and Kobe to Brisbane."
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