Struggling Southampton officially appoint Jones to replace Hasenhuttl
Hasenhuettl, who was in the top job at St Mary's for almost four years, was sacked following Sunday's 4-1 home defeat by Newcastle United, which left Southampton in 18th place after picking up only three wins from 14 league games.
The Austrian guided Southampton to an 11th-place finish in his first full season before finishing 15th in the next two campaigns. He also presided over two 9-0 defeats during his tenure, against Leicester City in 2019 and Manchester United in 2021.
Welshman Jones, who will take up the role ahead of Southampton's league trip to Liverpool on Saturday, will need to turn their fortunes around quickly or risk being drawn into a relegation battle.
"I'm really proud to be given this opportunity," Jones said in a statement.
The former Brighton & Hove Albion and Yeovil Town player ended a second spell as manager of Luton, having previously been in charge from 2016-19 - a period during which he guided them from League Two to League One.
An unsuccessful 18-month spell with Championship side Stoke City followed before Jones returned to Luton in 2020.
Jones said he had been impressed by the way Southampton is run as a club and that he had wanted to test himself in the Premier League.
"It's pretty amazing really. It's been a whirlwind time, but I'm really proud to be given this opportunity at a wonderfully traditional football club," Jones added.
"Obviously, I wanted to manage in the Premier League, I've dreamt of that since I've become a coach or a manager.
"But this club in particular – because of how it's run, because of the structure, because of how they look deeper than just results – really appeals to me."
First-team coach Ruben Selles took charge for their League Cup win over Sheffield Wednesday on Wednesday.