Mark Hughes says his "affinity" with Southampton is the reason he agreed to take charge of the Premier League strugglers until the end of the season.
The former Stoke boss replaces Mauricio Pellegrino, who was sacked on Monday with the club one point above the relegation zone after one win in 17.
"The objective is to make sure we're a Premier League club next year," Hughes said. "That's where we should be."
Hughes was sacked by Stoke in January, with the club in the bottom three.
The Welshman, 54, had been with Stoke for four and a half years and has taken charge of 445 Premier League matches for the Potters, Blackburn, Manchester City, Fulham, QPR.
He started his managerial career with five years in charge of his country.
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Hughes spent two years at Southampton from 1998 to 2000 in a 22-year playing career that also included spells at Manchester United, Chelsea and Barcelona.
"It's a challenge I'm excited by. It's a great opportunity to come back to a club I know well, and a club I've got real affinity with, and I couldn't turn that down," Hughes said.
"I understand what it takes in this league to win games. But it's about coming in and being that different voice that will enable the players to recognise and focus on what needs to be done."
Hughes' first game will be Sunday's FA Cup quarter-final against League One side Wigan.
Southampton were beaten 3-0 by Newcastle on Saturday and their next league game is away to fellow strugglers West Ham on 31 March.
Hughes is the club's fifth permanent manager in the five years since Mauricio Pochettino, now Spurs manager, replaced Nigel Adkins.
|Premier League record|
|Games||Win %||Points per game|
|Blackburn Rovers (2004-08)||147||39.5||1.45|
|Manchester City (08-09)||55||40||1.44|
|QPR (Jan 12-Nov 12)||30||20||0.8|