The 23-year-old defender has put pen to paper on a three-year deal at Fratton Park to become boss Paul Cook’s seventh summer signing.
Burgess told Pompey’s website: “This is a massive club and the set-up down here is great. I got a call from the gaffer, had a look round and everything was first class.
“It doesn’t feel like a League Two club – there are more fans here than at most League One sides.
“Hopefully we can move up the leagues and we want to meet the expectations that there are of us.
“I’m excited to be here and am looking forward to what is hopefully an exciting season ahead.”
Cook has also signed Kyle Bennett, Kal Naismith, Enda Stephens, Gary Roberts, Adam McGurk and Adam Barton this summer.