Mam had been free to negotiate with rivals for the 2025 season and was linked with a move to local rivals the Dolphins before inking an extension that keeps him at the Broncos through until 2029.
Mam, who has played 38 NRL games and celebrated his 21st birthday last week, now holds the longest contract of any active Broncos player.
"Ezra is a born-and-bred Bronco and it's great that he is staying where he belongs," said coach Kevin Walters.
"He is an exciting player but he also likes to get in there and do the tough stuff and to do what needs to be done for his team.
"We have only scratched the surface on what Ez can do - we'll keep on working with him to improve his game and I can't wait to see what we can achieve together over the years ahead."
Mam was the Broncos' best player in the 2023 grand final defeat, scoring three tries to cap off a breakout season that earned him the Dally M Five-eighth of the Year award.
His potential was recognised with selection in Queensland's 34-man pre-season camp last week, where he will be assessed as a State of Origin star of the future.
Mam joins teammates Pat Carrigan, Payne Haas, Corey Jensen and Deine Mariner in recommitting to the Broncos in the past 12 months.
Mam's halves partner and captain Adam Reynolds, who turns 34 this July, remains off contract at season's end.
22°C