Here, Press Association Sport looks at the 51-year-old's background.
A striker of international pedigree
Hasenhuttl moved from hometown club Grazer AK to make his true mark with Austria Vienna, winning three consecutive titles in the Austrian Bundesliga from 1991 to 1993. The forward scored three times in eight Austria caps, but could never force his way ahead of Toni Polster in the pecking order.
Launched his managerial career in Germany
After spells with Cologne and Bayern Munich's second team, Hasenhuttl retired from his playing career to move straight into coaching. And he stayed in Germany, moving from youth team coach to manager at Unterhaching. In his only full season at the helm he just fell shy of securing a play-off place in Germany's third tier.
Cemented his growing reputation at RB Leipzig
In two years in charge at the Red Bull club, Hasenhuttl secured a second-place finish in the Bundesliga, with the club performing better than a clutch of established outfits. It was here that Hasenhuttl's progressive playing style came to the fore.
Southampton view Hasenhuttl in the Pochettino mould
Southampton had banked on Mark Hughes succeeding at St Mary's owing to his wealth of Premier League experience. But just one win in 14 matches this season forced the board to dismiss the former Wales striker. Appointing Hasenhuttl would represent a return to the calculated-gamble approach of drafting in a progressive foreign coach yet to test their methods in the Premier League. This worked wonders with Mauricio Pochettino, now soaring with Tottenham, while the blueprint failed with another former boss, Mauricio Pellegrino.
The no-nonsense Austrian will drill his players
Hasenhuttl adopts a high-pressing system, which will put the onus on hard graft and top fitness levels at St Mary's. Saints can expect nothing but work in matches and training.