The 32-year-old former Bradford Bulls and Huddersfield Giants front-rower joined Trinity from Salford Red Devils on a one-year deal last autumn.
Kopczak, an ex-Wales International has featured in all Trinity’s six games so far this season and opened his try-scoring account on his debut in the round-one defeat at London Broncos.
He said: “I have been made welcome from the first day and I’m really relishing the new environment.
“The group of lads we have here are all great and I’m loving every minute of my time here.
“It’s bringing the best out of me and I couldn’t imagine myself anywhere else. I’m excited to be part of an outstanding squad we have.”
Trinity coach, Chris Chester reckons Kopczak has been at the top of his game since moving to Wakefield.
“He’s started the season exceptionally well for us and I would say he’s playing some of the best footy of his career too,” Chester said.
“He has added a lot to the pack and he is a really good guy to have around the place, so I’m delighted he’s extended his stay.”