Bradford City's League Two rivals move quickly to appoint ex-Newcastle United and Wolves man as head coach
A slow start to the season cost Graham Alexander his job at the club, as MK Dons parted ways with both Alexander and his assistant Chris Lucketti.
A former Premier League defender with Newcastle United, Williamson led Gateshead into the fifth tier before consolidating their place in the division.
He also led the Heed to the FA Trophy final last season, although oversaw a defeat to FC Halifax Town.
Williamson told iFollow MK Dons: “I’m excited and I can’t wait to get started. It’s been a quick turnaround and it was a tough decision to leave Gateshead but when a club like this comes in, it’s a no brainer.
“Everything the club epitomises was really attractive to me and my team. For us, it was about finding somewhere that was aligned with the way we see the game and would back us in doing that - this is the right club for us to do that.
“We have a talented squad, with strength in depth, and we’ll come in and start getting to know the group. They’ve got to trust us and buy into what we stand for - we have a lot of ideas that we want to implement, but it will be one thing at a time. It is going to be an evolution.”