The 22-year-old forward is a product of the Tigers’ youth system, coming through both the scholarship and academy programmes, before making his Super League debut in 2019.
And he says he did not want to go anywhere else and is delighted to extend his stay.
Speaking to castlefordtigers.com, O’Neill said: “I’m over the moon to stay at Cas, I’ve been at since I was 15/16 and it has a place in my heart now, I wasn’t really looking to go anywhere else.
“I’m happy here and I want to keep progressing in my career here.
“I’ve been here since the Under-16’s and I feel like it is like my home club now. I’ve lived here six years, my mum lives here and it’s close to me.”
The former Askham player has gained plaudits for his enthusiastic style of play, which O’Neill says has not changed since he first started playing rugby league.
“I think that’s just me since I’ve been young, in anything I do whether it’s away from the field or on it, I just want to try my best in everything I don’t want to lose,” he said.
“I want to win at everything even if it was a board game, I want to win it, I just don’t like losing.”
It was in the truncated 2020 season where the Cumbrian-born player really made his breakthrough, with 12 appearances and two tries.
Despite it being a stop-start campaign so far for Castleford’s number 18 due to injury, O’Neill has been called up for the England Knights squad alongside team-mates Danny Richardson and Jake Trueman.
Head coach Daryl Powell has developed O’Neill to be adept at both hooker and loose forward – with the player saying he now prefers the latter position.
With Powell leaving at the end of the season, O’Neill wants to send his mentor out on a high.
He said: “I remember when he got me in the office one year when I was still playing in the Academy and he went ‘I want you to play 13 instead of 9’, but all I’d known was hooker, and when he said that I was not too sure.
“Now, I think I have to thank him because I enjoy loose more than I do hooker, I feel like I can use more of my attributes there. But I would play anywhere for the team.
“Look what he has done for the club, he goes down in history because he’s done so much and turned it around, he’s brought players through to be their best and he deserves that.
“It’s the least we can do is try win the Challenge Cup for him, for the club, and for the fans, because everyone deserves it here, they’re so loyal and Powelly has been massive to it all.”
Lee Radford will be head coach in 2022. O’Neill admired Radford as a player and is looking forward to working with him in the next campaign – but insists that he remains focused on the current season at hand.
“He was an aggressive player himself (Radford), all intent, all aggression so hopefully he can take me to another level, but we’ve got this year to focus on.”
Radford said: “I like him, he is just full of energy, really game, plays with so much energy. Jacques is definitely someone that I am excited to coach because I think there is so much improvement in him as well.”
“A type of player that the club needs around, especially in that position as well. It excites me that he is still young and there are areas of his game where he can get better at and hopefully, we can get the best out of him.”