Buhrer joins the Club from the Manly Sea Eagles, on a two-year contract.
Buhrer made his NRL debut in 2010 and has played 120 games for Manly, including a premiership in 2011.
The 26-year-old can play in the second-row, at lock and hooker.
“Jamie is a natural footballer and a player that covers a number of positions,” coach Nathan Brown said.
“Importantly Jamie is a mature player and will help with the growth of our younger players.
“Jamie is a good leader, trainer and talker, and will be an important addition to our squad.
“He knows what is required to win and what it takes to win a grand final; he really comes to Newcastle with great experience.”
Buhrer will commence pre-season with the Knights on November 1.