Titans rookie Max King with father David (left) and grandfather Johnny (right) following his NRL debut.

It's the prerogative of grandparents to spoil their grandkids rotten.

Whether it's a bit of lenient baby-sitting, a sneaky bag of lollies that mum and dad never see or $10 to buy a toy they probably don't need, grandparents do whatever they can to stay in the good books.

‌Max King's grandfather displayed his affection in a slightly different way but Max King comes from a rather rare family.

The 19-year-old made his debut for the Titans last Saturday night against the Eels and in so doing became the fourth generation King to play rugby league at the highest level in Australia, the Kings only the second family to have achieved the feat.

His great grandfather Cec played two seasons for South Sydney in 1945-46, his grandfather Johnny was a 15-Test representative for Australia and one of the most prolific try-scorers in the game's history and his father David played two seasons for Gold Coast in 1991-92 before an extended stint playing in England.

Given his lineage it was somewhat inevitable that Max and his older brother Oliver would at least dip their toes into rugby league but when Max's passion turned into an obsession in his early teens Poppy played his important part.

"I always felt his love but he was hard on me in pre-seasons," Max told NRL.com.

"Back in those days (Johnny King played 12 seasons for St George from 1960-71) it was 13 men a side so you had to be fit so I used to do some pre-season with him just to get fit.

"He was big on track work so we'd do a lot of track work and there were some gruelling sessions doing that.

"The Thornton footy field had a not really well maintained running track and there was no shade, nothing.

"We'd be there in the middle of summer and I'd go home thinking, This bloke is not good for me."

David King knew all too well what Johnny's philosophy on footy fitness training consisted of and credits Max's fast-tracked elevation to the NRL to his exhausting fitness sessions with his grandfather.

"He knows it comes down to hard work and effort. He used to condition Max," David said of his legendary father.

"He used to take him down to the local football oval and flog him basically. Loads of 200s and really work on his speed and his endurance.

"He's put a hell of a lot into Max with his development. He's a real hard task-master when it comes to fitness and watching the game.

"He played for St George for all those years but he also coached South Sydney first grade in '75 and '76 and he knows the game.

"When [Max] went to the Titans and he was training full-time, what they're doing up there is very similar to what his grandfather was training him on the field.

"It goes to show when it comes to fitness in rugby league it hasn't changed that much in 50 years. You still need that stamina and endurance even though the game is played in faster bursts nowadays."

Of course, with such a family history in the game there was always the possibility that Max could have rebelled and gone down a different path.

He said his parents David and Caroline were supportive in everything he tried his hand at but has no doubt the guidance of his father and grandfather enabled him to develop his football knowledge far quicker than other kids.

"Having that rich history I got introduced as a kid and the love grew," said Max.

"As I grew into the early teenage years that's where that passion turned into an obsession. I had to crack it.

"There was never any pressure but with the knowledge they had they could give me guidance through my whole childhood, rather than just seeing a coach every Tuesday and Thursday.

"Dad would sit down with me after a game and just tell it how it is. If I had a bad game he'd spray me, if I had a good game he'd be 100 per cent honest and I reckon that's the reason why I'm here today.

"Dad and my grandfather were there critiquing and helping me to improve week by week, year by year.

"As I've got older Pop has taken more of a back seat and he's just happy to see my success."