The 32-year-old Henry announced yesterday that he had agreed to leave Barcelona to take up a "multi-year" deal with the Red Bulls.
"This marks an exciting new chapter in my career and life," he said in a statement released by the New York team.
The former Juventus and Arsenal forward will join England's Beckham and former Swedish international Freddie Ljungberg among the league's "designated players" who have most of their salary paid outside of their team's salary cap.
Henry is expected to play his first match next week when the Red Bulls host English Premier League team Tottenham Hotspur at their new stadium.
"It is without question that Thierry Henry is one of the most successful and recognisable soccer players over the past 15 years," said Dietmar Beiersdorfer, head of New York's owners, Red Bull Global Soccer.
"We are thrilled that Thierry has decided to come to New York to help the Red Bulls compete for championships this year and for years to come. His international pedigree is second to none and he is a proven winner." The Red Bulls have recently moved into a new, purpose-built stadium in New Jersey but have yet to win an MLS title and are pinning their hopes on Henry.
"I am fully aware of the team's history and my sole goal during my time here is to help win the club its first championship," Henry said.