Kenny Jackett believes Lee Brown's arrival will help shore up Pompey's defence.
He moves to Fratton Park on a free transfer from Bristol Rovers after opting to leave the Memorial Stadium.
Brown has more than 250 Football League appearances under his belt.
Jackett believes that nous can strengthen Pompey's rearguard in their bid for promotion to the Championship next season.
And the Blues boss feels his new signing's better days are still ahead of him.
Jackett said: 'Lee brings an awful lot of experience to our side and yet he probably still has his best years in front of him.
'I felt we gave away too many goals last season and he can certainly help with that, but he’s also a full-back that likes to attack and create goals.
'We’re really pleased to bring someone of his character to the club and I believe he’ll really add to our group.'