The 22-year-old failed to make an impression at White Hart Lane after signing a professional contract as a teenager. He spent time out on loan with a number of clubs, including a spell with the Cherries as they reached the League One play-offs in the 2010-11 season.
Smith has now rejoined Bournemouth on a three-and-a-half-year deal and he is looking forward to making the Goldsands Stadium his new home.
"It's great to be back. My loan spell here a few years ago was successful and I've worked with Eddie Howe before, so it just feels right," he told the club's official website.
"I've had seven loans and I was looking to stay at one club for a while. At this stage in my career, I need to have a home.
"Hopefully I can do that here because I'm here for the long term and want to help Bournemouth be successful."
Cherries boss Howe was delighted to welcome Smith back to the club.
"We know Adam from our first spell here and I think that is really important for us. When you get to work with players, you get to know their strengths and we certainly know what Adam can bring us," Howe said.
"He fits the right age profile and is someone we can now really enjoy working with for the long term. He is going to be a good addition to the squad."
Smith is not expected to feature for Bournemouth in Tuesday night's home clash with Huddersfield.