Sharks captain Paul Gallen.

Paul Gallen has confirmed his 19th season of top flight rugby league will be his last, with the inspirational Sharks skipper to retire at the end of 2019.

A day before he equals Cronulla icon Andrew Ettinghausen's 328-game record for most appearances in the black, white and sky blue, Gallen told KIIS FM he has "had enough of the rollercoaster" that is first grade rugby league.

"I'm going to retire from rugby league this year," Gallen said on Friday morning.

"I've really enjoyed where I've been and what I've done but I'm ready to retire.

"I've just had enough of the rollercoaster, the up and down.

"Even this time last year, I was going through things and thinking, the only reason I'm going to retire is because of my age, I'm still performing a role, I'm still doing it, liking it.

"But I've come this year and I'm still performing... but like I said before, it's the rollercoaster of turning up."

Paul Gallen raises the 2014 Origin shield.
Paul Gallen raises the 2014 Origin shield. ©NRL Photos

From Parramatta's juniors to a 2001 debut in the halves, through wooden spoons, ASADA bans and salary cap scandals to a cherished 2016 premiership, few rollercoasters have taken as many turns as Gallen's.

Controversy was courted early with a series of grubby on-field acts that prompted a career-changing dressing down from coaching ornament Ron Massey.

Headlines have never been too far away with forthright views and a willingness to express them, but Gallen's true status as one of the modern game's most durable performers has come to the fore over the past decade.

At 37 he is the oldest player in the 2019 competition but still boasts one of the game's biggest engines, becoming the first player to clock up an astounding 50,000 running metres early last year.

With another six months left at the top level Gallen remains a chance of joining the elusive 350-game club, occupied by only Cameron Smith, Darren Lockyer, Terry Lamb and Cooper Cronk.

Already he boasts 32 Test appearances for Australia and 24 for NSW, captaining his state to a drought-breaking 2014 series win after enduring more pain than any other New Southwelshman in Queensland's eight straight series wins.

Gallen's end-of-season retirement is no great shock, but the timing and early-season call are.

It comes without the fanfare of a club announcement or even a press release, just one game into the new reign under rookie coach John Morris.

An early call from his skipper avoids the 'will he or won't he' sagas that have followed Gallen in the autumn years of his career, and also allows the Sharks to build beyond 2019 with more certainty around their roster.

As well as his growing media platform and boxing pursuits, Gallen can see himself transitioning into an assistant coach role once he hangs up the boots for good.

"I'll do a little bit in the media with Channel Nine, so really enjoy that, the commentary and the talk shows," he said.

"I'll stay involved in the game whether it be with Cronulla or a club with a little bit of a mentoring role."