9th November 2017, 17:23 | wakefield_trinity
Hirst joined Trinity from Batley Bulldogs on a 12-month deal with an option of a further year that has now been triggered.
"I am really happy for Keegan," said Wakefield head coach Chris Chester. "It was a big step up for him to come in and play at Super League level every weekend but he has achieved that and had a great season.
"I am looking forward to working with Keegan for another year and see him grow even more as a Super League player."
The 29-year-old made 23 appearances for Wakefield in 2017 and ended his debut season on a high by scoring his first try in the dying stages of the 32-0 win over Wigan Warriors in the final game of the Super 8s.
"I am really happy to be staying with Wakefield," said Hirst. "It is a great club that's doing its best to move forward both on and off the field.
"We have a great group at the club and the fans have been fantastic.
"I really enjoyed my first season and I am looking forward to getting stuck into pre-season and kicking on for 2018."