The 28-year old brings 194 games of NRL experience after making his debut with the Brisbane Broncos in 2009.
McGuire also has made 10 appearances for Queensland, eight for Australia and seven for Samoa, providing depth to North Queensland’s forward pack.
Cowboys coach Paul Green was excited to reunite with Green, having coached the veteran enforcer during his junior days.
“I coached Josh as a junior at both the Queensland Academy of Sport and the Broncos Academy and have followed his career closely,” Green told cowboys.com.au.
“His development over the years has really impressed me and to reconnect and have the opportunity to work with him again is something I’m personally really looking forward to.
“I’m really excited about what Josh can bring to the Cowboys.”
Cowboys director of football Peter Parr was also thrilled by the signing a player of McGuire’s ilk.
“We have been looking to strengthen our squad by signing another quality middle forward and clearly as a current Australian and Queensland player Josh fits that bill,” Parr said.
“As a player he has the attributes other players like to have in a teammate and we are excited to have someone of Josh’s quality joining the likes of Jordan McLean, Matt Scott, Scott Bolton and Jason Taumalolo in the middle of the field.