And the Reds have appointed Nathan Kosmina, son of ex-coach John Kosmina, as chief executive officer after being acting CEO for the past year.

Vidmar was Adelaide's inaugural captain and also the Reds' coach from 2007-10 before joining the Australian set-up, where he had stints as a Socceroos assistant and coach of the under-23 national team.

"It means a lot (to come back), it has been a massive part of my playing and coaching career," Vidmar told reporters on Wednesday.

"I'm very pleased. Obviously it's going to be a big challenge but nothing that hasn't been thrown my way in the past."

Vidmar was most recently manager of Bangkok Glass in Thailand in 2016-17 but said he had no ambition to again coach the Reds.

"That is definitely not going to happen while I'm in this role," he said.

"I have to make that crystal clear, it won't happen."

Vidmar infamously described Adelaide as a "piss-ant town" after coaching United to a 2009 A-League semi-final loss, saying at the time the club was riddled with internal politics and hidden agendas.

"You had to bring it up," Vidmar said on Wednesday.

"What is extremely important is that there is football people here now and that is exciting.

"The board is extremely impressive and just with views and discussions I have had over the last couple of weeks has convinced me enough to say that the club is heading in the right direction."

Vidmar said his role would encompass United's men's, women's, youth and academy teams.

Australian Associated Press