Appleton moved to Bloomfield Road as successor to Ian Holloway, who ended a highly-successful three-and-a-half year stint with the Seasiders to join Championship counterparts Crystal Palace at the weekend.
He told Sky Sports News: "I'm absolutely delighted. It's an opportunity that I didn't see coming but one that I'll hopefully take with both hands."
The 36-year-old former Manchester United youngster had his playing career cut short by a serious knee injury but has impressed in his first managerial role, earning plaudits in difficult circumstances at Portsmouth.
Appleton, who has signed a one-year rolling contract, left Portsmouth after an eventful year at Fratton Park which saw the club placed in administration and relegated to League One.
He said: "It was a situation where there was a lot of speculation regarding myself and other jobs not too far away from here over recent weeks, but I think an opportunity to get back into the Championship at a club who have been very competitive over recent seasons was one that I didn't feel I could turn down."
Appleton told Blackpool's official website. "I met a few of the coaching staff a little bit earlier, we just had a bit of a chat and I got a feel for the place. I'm just desperate to meet the players now and crack on with the job."
And the 36-year-old assured fans that Blackpool's style of play is not set for any drastic overhaul.
He added: "As a new manager coming in you want to bring a few ideas to the new football club and the team but I think they've got to be small steps in doing that because if it's not broken then don't mend it, just tweak it a little bit."
Blackpool, who led the table in the opening weeks of the season, lie 12th in the Championship after earning a first win in six outings at Sheffield Wednesday on Tuesday.
Appleton previously worked at West Brom as assistant under Chelsea boss Roberto Di Matteo and England manager Roy Hodgson.
Chairman Karl Oyston said: "Everywhere Michael's been people speak very highly of him - of his work ethic and coaching talent.
"He's very motivated and certainly what he's been through over the past 12 months at Portsmouth, I think he's done very well and coped with probably the most difficult circumstances in football and come out with very extreme dignity.
"People have a high opinion of him."
Ashley Westwood also makes the move north from Portsmouth and will serve as first team coach.
Steve Thompson, who served as caretaker boss in the two games since Holloway's departure, will remain as assistant manager.