Bridge, 31, has arrived at the Amex Stadium to begin his third spell out on loan since joining City in 2009, having previously spent time at West Ham United and Sunderland.
Brighton manager Gus Poyet told the club’s official website of his delight at being able to bring a player with such extensive international, European and top-flight experience to the Championship club.
He said: "It's difficult to say how I happy I am because it's not easy to get top-class players. I'm absolutely delighted to have Wayne with us. He's been one of the top three left-backs in this country for many years.
"There were a lot of things that had to come together to make it happen. Firstly, David Platt has been great at Manchester City and then Wayne and his agent have helped a lot too.
"It was not an easy one to secure, but this is what we want at this club. He's a quality player with lots of international experience.
Potentially one of Bridge’s first matches for Brighton will be a pre-season friendly on August 4 against former club Chelsea, where he won the Premier League, FA Cup and League Cup during a successful six-year spell.