Crouch agreed a four-year contract with Harry Redknapp's side, who are believed to have paid Liverpool £11 million (13.7 million euros) to secure his signature. The 27-year-old said that he can't wait to link up with Redknapp for the third time in his career, having played under him in his previous spell at Portsmouth in 2001-02 and also at Southampton.
"I've worked with the manager before and he gets the best out of me," Crouch said at his official unveiling at Fratton Park. "It's fantastic to be back. This club is going places and they can match my ambitions."
Crouch was unable to hold down a regular place in the Liverpool team during his time at Anfield, so the prospect of being a key player with Portsmouth was a major factor in his move. "The chance of regular first team football was part of the appeal. I know I'll have to work hard to prove myself in training, but I believe my best years are in front of me," he said.
Redknapp, who will pair Crouch with England team-mate Jermain Defoe in Portsmouth's front line, admitted the signing showed how far his club has developed in recent years.
"Bringing a player like Peter here shows how far we have come and how far we can go," Redknapp said. "I never expected to see him back here. He went off to Liverpool and did a fantastic job in my opinion and I'm looking forward to seeing him and Jermain Defoe up front - a big one and a little one - and we've got other good forwards here.
"He'll be a real threat here, a real handful. He has great ability and is a tall lad so you can drop balls off him and he's great at bringing people into play. There's no reason why he can't get a lot of goals here this year."
Crouch becomes Portsmouth's fifth England international and Redknapp believes Fabio Capello will be a regular visitor to the south coast next season.
"When you look at our team we have David James, Glen Johnson, Sol Campbell, Peter and Jermain Defoe," he said. "We have five players Fabio wants to keep an eye on this year."