The 52-year-old left Reading on March 11, with the Royals' hierarchy worried about relegation from the Barclays Premier League, but was not out of the game for long, signing a three-year deal at Elland Road. He replaces Neil Warnock, with the veteran boss having fallen on his sword last week after failing to deliver promotion.
McDermott, who won the division with Reading last year, was approached immediately by Leeds' owners with the intention of taking over in the summer but, with United not safe from relegation, he has been brought in now. "I was approached about 10 days ago and the conversation was about coming in the summer," McDermott said.
"But things have escalated, I spoke to Shaun Harvey (chief executive) who wanted to put a manager in place now and that was something I had to think long and hard about for a couple of days, and it feels right. The whole place feels right.
"I wouldn't have taken a job at this stage of the season anywhere else. It's a massive club and I don't need to be told about the history."
Leeds have acquired a reputation for selling their best players over recent years and the futures of some of their leading names - such as Sam Byram and Tom Lees - are expected to be in McDermott's in tray.
The club have also been accused by some of their fans of not investing in the playing staff and, with McDermott yet to discuss budgets, he admits to having taken a leap of faith.
"The question about money available will be answered, I don't know the answer and have come here on a lot of goodwill," he said. "I want to take this club forward, but no one person can do that on his own. Everyone has to be going in the same direction.
"But I live in the real world. At Reading I lost Gylfi Sigurdsson, a player who scored 20 goals for me and I lost Shane Long. When he left I thought there was no way we could win the league, but we did. And that showed me you can never rely on one player.
"But I don't want to lose anyone. The best place for the young players is here, playing in front of these fans."
Source: PA
Source: PA