Cougars head coach Alan Kilshaw said: “It’s sad to lose Jack and I know his affinity with the club is strong.
“He’s remained extremely professional throughout my time with him and I thank him for the work and determination since I’ve been here.
“With Jack’s contract drawing to a close at the end of the 2025 season, it makes sense for him to consider his options for 2026.”
Regular goal-kicker Miller leaves Cougars having amassed 977 points during his seven years at the club, making him their second highest scorer of all-time behind Keith Dixon.
Jack Miller dots the ball down against York in this year’s Betfred Challenge Cup for one of his 52 tries in Cougars colours. (Image: JT Sports Media)
Commenting on his own departure, Miller said: “I want to thank the club for the great years.
“There have been some ups and downs but overall, more good than bad.
“A big massive thanks to the fans for sticking with me and the team throughout my time in Keighley.
“Killer has come in and wants to take the team in a different direction and I fully respect that.
“I feel the time is right for me to move on and this allows the club to move on too.
“I’ve nothing but great memories, once again, thank you and I will see you all soon.”
Cougars’ board of directors said in a statement: “Jack will go down as a Keighley legend and none of us will ever forget that 2022 unbeaten season where he won (League 1) Player of the Year.
“It’s been a tough start to 2025 and Jack has remained positive and professional with the club keeping on-field success as his number one priority.
“Jack has given us memories to last a lifetime and for that, we thank you and wish you all the best in your next move.”