Subject to stakeholder approval and international clearance, the 30-year-old forward has put pen to paper on a three-and-a-half-year deal at the Racecourse Ground, through to June 2025.
With Hollywood stars Ryan Reynolds and Rob McElhenney now owning the Welsh National League club, their budget has allowed them to bring in a player that has blossomed since failing to make an impact in his time at the One Call Stadium.
Palmer caught Mansfield's eyes with 37 goals in 69 games for non-league Havant & Waterlooville.
He signed on 2nd August 2013 on a two-year contract for an undisclosed fee and debuted a day later as a 61st-minute substitute in a 2-0 defeat away to Scunthorpe United.
Palmer scored his first Mansfield goal in a 1-0 win away to Wycombe Wanderers on 17th August, but struggled to find the net on a regular basis.
In the end he scored just seven goals for the club, five in the league, having started 26 games and come on in 38 others from the bench.
After a spell at Grimsby, Palmer found his scoring feet again at Crawley Town where he hit 27 goals in 68 league games.
On his latest move, Palmer said: “I’m excited. It’s a brand new opportunity for me and something I really wanted to be involved with so I’m looking forward to it.
“I had a good conversation with the gaffer here, and he really sold it to me. The passion around the town for the football club; it’s obviously one of the oldest football clubs around and it’s just about getting them back to where they want to be.
“We have some really famous co-chairmen, and they have already done some amazing things with the club. It’s just a really good opportunity for me – something to get my teeth into, something new.
“Phil Parkinson explained everything to me, and it was something that got me really excited.”
Palmer has scored eight times for the Dons this season and leads their goalscoring charts, now having netted 111 league goals in 402 career appearances.
Manager Phil Parkinson said of the signing: “I’m absolutely delighted. Ollie was a player we wanted right from the offset.
“These things take time, and they can be difficult, but credit to Rob and Ryan for sanctioning the deal and to everyone else involved in getting the deal over the line, because when you’re attracting a player from a higher league, the deals are never easy. I’m absolutely delighted we’ve finalised the signing.
“He gives us presence, but he’s also got quality and that was important for us – we want good footballers. He’s got good technical ability, he’s a good character and he’ll be an excellent addition to the squad.”
AFC Wimbledon reluctantly accepted the offer from Wrexham after the player insisted he wanted to leave the club.
Dons chief executive Joe Palmer said: “Wrexham offered a substantial fee for Ollie - and also made him an irresistible personal offer.
“In the end, though, it was entirely Ollie’s decision to leave.
“We couldn’t have offered him anywhere near what he was being offered and the last thing we wanted to do was force him to stay against his will. That wouldn’t have been in anyone’s best interests.”
Palmer sent a final message to Wimbledon, saying: “I just want to say a massive thank-you to each and every one of you.
“You’ve helped me grow as person and been a second family to me. I got to say a few goodbyes this morning and obviously in the players' group chat.
“I wish you nothing but the absolute best this season, what a club to play for, and thank you for everything.”
Their head coach Mark Robinson said: “As a coach, seeing a 30-year-old grow and develop as a player and a person was hugely satisfying.
“I am obviously really disappointed Ollie has gone, but I can only wish him the very best as he bought into everything we did and had a big impact for us.”