The American was a likely candidate to succeed Marcelo Bielsa at the close of the 2021/2022 season, but the sacking of the former United manager forced the move to progress quickly.
In February, Marsch was offered the chance to take charge of a team in crisis with the huge mandate of steering them clear of relegation - and he wasn’t completely sure whether or not to accept.
“I knew there was an opportunity when Victor [Orta, director of football] asked me to come at a time that I, frankly, didn’t want to come,” Marsch said.
“From the beginning, when Victor asked me to come - at first I was like ‘no’. Then I thought about it for 24 hours and it was an opportunity.”
The Whites wrapped up their first signing of the summer transfer window on Thursday, with USA international Brenden Aaronson joining the club on a permanent basis from RB Salzburg.
Check out the latest Premier League transfer speculation below...
7. Toon confident on Saint-Maximin future
Allan Saint-Maximin looks set to remain at Newcastle United next season, but the winger is likely to want parity with the club’s top earners. The Toon Army are confident that the Frenchman will stay put on Tyneside. (Daily Mail) | Getty Images
8. Brighton still keen on Braithwaite
Brighton ‘remain interested’ in signing Barcelona striker Martin Braithwaite this summer. (Sport) | Getty Images
9. KIRKBY, ENGLAND - MAY 25: (THE SUN OUT. THE SUN ON SUNDAY OUT) Takumi Minamino of Liverpool with Harvey Elliott of Liverpool during a training session at AXA Training Centre on May 25, 2022 in Kirkby, England. (Photo by John Powell/Liverpool FC via Getty Images)
Leeds United are leading the race to sign Liverpool attacker Takumi Minamino. (SkyBet) | Liverpool FC via Getty Images