Kapo signed a three-year deal after completing a medical and followed Daniel de Ridder in moving from Birmingham to the JJB Stadium this summer.
Kapo said: "It's fantastic to be signing for a club like Wigan. As soon as I spoke with Steve and he told me his plans for the next few years, I wanted to come.
"Steve is a fantastic manager and this club is going places. I really want to be playing for them now."
Bruce was delighted to have secured his services once again.
He said: "Yes, he's one I really wanted to get on board.
"Olivier's a real fighter, but he has a touch of quality about him.
"He can play in a number of positions and having worked with him in the past, I know what a good addition to our squad he will be.
"He has Premier League experience, which is important, and I'm confident he will do well here."