The 30-year-old midfielder has starred in three promotion-winning campaigns since joining the Hatters from fellow League Two side Cambridge United in August 2017.
Berry had forged a reputation as one of the finest goalscoring midfielders in the lower divisions while helping Cambridge to National League promotion alongside the Hatters in 2013-14, earning a move to League One Barnsley before returning to the Abbey after one season.
In his first season at the Kenny, he netted eight times in 39 appearances to help seal League Two promotion, although he ended the season sidelined by a serious ankle injury.
He returned the following campaign to score three goals in 24 appearances as the Hatters won the League One title to secure promotion to the Championship, where he then helped the club establish itself over four seasons and win a third promotion while taking his tally to 24 goals in 164 appearances.
The last of those games came as a substitute in the play-off final win over Coventry at Wembley last month, where the man known as ‘Bez’ stepped up to convert his penalty in the victorious shoot-out.
After putting pen to paper on a deal that will see him play in the top-flight for the first time, Berry said: “That was the best achievement of my career, and to do it at Wembley with this group of players made it even more sweeter. It was the best day of my career by a mile.
“It didn’t properly sink in until I saw the badges, and who we were playing. Our badge was in the mix with all the Liverpools, Man Uniteds and Chelseas, and when you look at that and think, what an achievement we’ve made to be amongst the big teams like that. Now we’ve got to try and stay there with them.
“It’s great to sign a new contract. I’ve said it in previous interviews but I love playing for the club, I love playing at the Kenny, and long may it continue with all the success we’ve had previously. Hopefully there is more to come.”
Manager Rob Edwards said: “I’m delighted to get Luke signed on again. He is someone who has just grown on me and grown on me the more we’ve been here. He knows this as well. He’s just got better and better.
“His availability for us has been brilliant and from his last-minute equaliser against Millwall, which was a really good goal, to his penalty in the play-off final, I think he’s just shown real moments of quality.
“When he came on early for Pelly up at Sheffield United, I thought he was outstanding and he backed that up against Bristol City, then away at Sunderland as well. He’s just performed really well, whenever we’ve asked him to, and he’s a really valuable member of the squad.
“Not only that, he knows the club inside out and we’ve got to stay true to ourselves, we have to keep that heartbeat, keep that core of people who have helped us get to where we’ve got to.
“These lads who have won several promotions with us, they are special and we’ve got to celebrate that. He thoroughly deserves to get a crack in the Premier League and I love him to bits. He’s class, a brilliant man who brings so much to the club.”
On the manager, Berry added: “Since Rob came in, he's been brilliant with me personally, and along with Richie and Trolls they’ve had a real impact on the squad. They’ve not transformed it from what was happening previously, but have changed a few bits that have really made us a better team, and that showed in the second half of the season.
“I can’t wait to get back to work now. It’s all about getting pre-season done, having a really good camp and being ready for the season ahead. It’s going to be a good test just to see where we are at, and I feel like we can cause a few problems.”