Former Brighton left-back arrives at Fratton Park
Pompey have signed Marcos Painter in a deal the runs up until the middle of January.
The 26-year-old left-back was a free agent having left Brighton at the end of last season.
He said: "I’m used to life down on the south coast and I’m excited to be joining a great club like Pompey, who have such a fantastic fanbase.
"This club is an attractive proposition whatever league they’re in. There’s a lot of work to be done and it’s up to the players to take Pompey back up.
"I enjoy defending and hopefully I’ll be able to use my experience to help the team do well this season."
Blues boss Guy Whittingham said: "Marcos is an experienced player, who has competed at a high level. He’s a good out-and-out defender and we’re pleased he’s come here.
"I think he was impressed with the vision of what we want to achieve here, while we were impressed with his attitude."
Painter came through the ranks at Birmingham before signing for Swansea – initially on loan – in 2006.
He then moved on loan to Brighton in January 2010, making the move permanent at the end of the season.
Painter made a total of 100 appearances for the Seagulls and also spent time on loan at Bournemouth last term.