The Tigers academy graduate has enjoyed a breakthrough season with the club in 2019, making his debut off the bench against Hull KR in round four of the Betfred Super League and going on to make seven appearances for the first team.
His performances have now earned O’Neill a 12-month contract extension that will keep him at the Mend-A-Hose Jungle until at least the end of the 2020 season.
Speaking to Tigers TV, he said: “I’m really happy to sign again with a great club. I’ve been here four years now and am starting to get a look in at first team level.
“Every time I’ve played I’ve enjoyed it more and more but this deal doesn’t make me feel any more comfortable, I’ve just got to keep working hard and keep chasing Macca (Paul McShane) and Adz (Adam Milner) for a place in the team.
“I know I’m behind them at the moment and I need to keep chasing them, they’re two of the best players in the league and I’ve learned a lot off them both. They’ve taught me lessons that I had to learn and without them I don’t think I’d be here now.”
Head coach Daryl Powell praised O’Neill this week following his display against Hull KR.
Of the new deal for the player, he said: “I’m really pleased for Jacques as it’s been tough for him this year. He hasn’t really played that much rugby league and we’re then asking him to go into the Super League arena and compete, but he’s done a great job.
“He’s a tough character, he can play nine and 13 and he’s done well in both roles so I’m delighted he’s agreed to extend for another year.
“Next year is a big year for Jacques, he’s got something a bit different about him to the other options we’ve got in those positions and I’m looking forward to seeing him develop further into next year as we move through this next pre-season.”
Director of Rugby Jon Wells added: “We are delighted to announce the re-signing of Jacques for 2020.
“He has progressed well despite an injury setback towards the end of pre-season and when called upon this season has shown us what he is capable of.
“If Jacques continues to apply himself in the manner in which he has this year, he can expect much more first team rugby as a Castleford Tiger in years to come.”