Heighington, 35, has totalled 334 appearances in the NRL over 16 seasons, playing at the elite level across three NRL clubs.
Heighington played 202 games for the Tigers, including being a part of the 2005 premiership-winning team, before making the switch to the shire, where he completed five seasons and became a dual-premiership winner in 2016.
After signing a one-year deal with the Knights in 2018, Heighington is set to hang up the boots at seasons end and will finish eighth on the all-time games record list for the NRL.
The English international has represented his country in the 2011 Four Nations tournament before earning a recall to the Lions for the 2017 World Cup.
Heighington told Knights.com.au it is the right time to end what has been a stellar career.
“A lot of ex-players told me I would know when it’s time, but I haven’t felt that feeling yet, but I do know the pre-seasons are long and another year is a big ask,” Heighington said.
“I want to go out on my terms. I’m still playing injury free and I don’t want to be greedy.
“I could try and continue to play but I risk picking up a bad injury or slipping in form, so I feel it’s my time to move over and let one of the young boys come in.”