Pardew has signed a three-year contract that will keep him at St Mary’s until 2013.
The 47-year-old left Charlton in November.
New Southampton owner, Swiss businessman Markus Liebherr said: “We are delighted to have been able to attract Alan to St Mary’s from a very strong field of candidates we identified and who expressed an interest in joining us.
“Alan has a strong track record and impressed us with his vision, commitment and ambition.”
“I’m proud and very excited to be joining a club with an immense history and huge potential,” Pardew said.
“Everything is here in terms of quality of stadium, training facilities and, now, financial stability.
“I’m look forward to working with the squad and with the executive management as part of a team committed to achieving progress.
“Of course, I will bring my own style of football management to the club, but as part of a plan being evolved at the club to achieve long-term success.”
