The 24-year-old will join Hearts on a three-year contract in the summer, admitting he believes the Gorgie club will give him "the best opportunities going forward".
Laszlo is pleased to have secured Barr's services, especially with Jose Goncalves almost certain to leave the club at the end of the season when his contract expires.
"I am pleased that we will welcome Darren to Hearts," said the Hungarian.
"He is a good player, a Scotland international, and he will bring experience to the squad, which is important.
"We look forward to welcoming him to Hearts this summer."
Barr's future has been the subject of much speculation and it looked a possibility that he could rejoin his former Falkirk boss John Hughes at Easter Road.
However, Hearts, Aberdeen and Dundee also took the opportunity to talk to the player over the past few weeks and, after weighing up the offers on the table, Barr has decided Hearts are his best option.
"While I am looking forward to making the move, my immediate priority is, as captain of Falkirk, to lead them away from the relegation zone in the SPL," Barr said in a statement released by his management company, 110 Sport. "I have enjoyed my time at Falkirk, and while there was an option for me to leave in this transfer window, I have always stated I was happy to see out the remainder of my contract and the season with the club.
"I want to leave on the best of terms with everyone at the Falkirk Stadium and keeping the club in the top flight will go a long way to guaranteeing that.
"But it goes without saying that I am thrilled with the prospect of joining Hearts, who I believe, will give me the best opportunities going forward."
Barr earned his first cap for Scotland in a 0–0 friendly draw against Northern Ireland at Hampden in August 2008, becoming the first Falkirk player to play for Scotland since John White in 1959.
He retained his place and was named in George Burley's squad for Scotland's World Cup qualifying matches against Macedonia and Iceland.
Hearts have been praised by Falkirk for their handling of the matter. Falkirk's head of football development, Ross Wilson, said: "Heart of Midlothian Football Club has conducted their business impeccably during all discussions with Falkirk FC and Darren."
Falkirk manager Eddie May added: "Hearts were happy for Darren to finish the season at Falkirk. They never forced the issue to try to get Darren now because it was always his intention to stay at Falkirk to help us in the situation we are in."
Meanwhile, Hearts could be about to be hit with a 10,000 fine today when the SFA look at how clubs have fared on the disciplinary front in the first half of the season.
When the Gorgie club were fined a record 50,000 in August for their poor discipline last season, a portion of that was suspended and they've failed to clean up their act.