The 27 year-old moved to stadium:mk for an undisclosed fee last night (July 20) after a lengthy pursuit by the League One club.
“I knew there was interest from them back in January and then again this summer. My agent presented me with a few teams who wanted to sign me and I felt MK Dons was the right team for me.
“I am very excited to work under (manager) Russell Martin, as he was a huge influence in me making my decision to join the Dons.
“I’m looking forward to the style of play as I feel it plays to my strengths and will give me the opportunity to score goals.
“I am a goalscorer, but most importantly I am a team player and I always try to do my best for the team to win.
“I’m excited to play in a stunning stadium and can’t wait to make my debut in front of fans - hopefully I can score loads of goals for them.”
MK Dons boss Russell Martin, the former Posh player, added: “This is a massive signing for us. He comes with brilliant experience at the level.
“He’s a proven goalscorer and that has earnt him a couple of big moves. That’s great credit to him.
“Mo is really hungry to do well and that desire has been a huge reason as to why this move has finally been completed.”
Eisa 21 goals in 69 games (45 starts) in all competitions for Posh. He scored twice in a 4-0 win at MK Dons in one of his earliest Posh appearances.