Schneiderlin looks set to make his United debut in the early hours of Saturday morning against Mexican side Club America in Seattle.
Next month he is likely to realise his childhood dream of playing in the Champions League for United in their potentially tricky play-off tie.
Such a feat would have seemed unthinkable five years ago, when Schneiderlin was preparing for Southampton’s League One season-opener against Plymouth, which they lost 1-0.
But the Frenchman would have had it no other way. The £24million midfielder believes his experience of playing in the lower reaches of English football has made him into what he is today.
“It seems a long way away, but when I look at it I think it (playing in League One) benefitted me,” Schneiderlin said.
“I think it was the best thing possible.
“I had to toughen my play, look myself in the mirror, and look where to progress.
“It makes you realise you don’t want to be back there (again).
“That makes you work even harder and that’s what I did.”
After two years in the third tier of English football and three in the Championship, Schneiderlin helped Southampton achieve promotion to the Premier League, and he has not looked back since.
After a series of commanding displays in midfield, the France international attracted interest from Tottenham and Arsenal last summer, but he is happy he waited for United’s call.
“I was waiting a long time (to move),” he said.
“I could have left before but I felt this was the right move for me.
“I feel physically in the best shape possible, and I feel with my confidence levels that I am ready now to move to a big club.
“Today I am the happiest person in the world to sign for the biggest team in the world and last year I had a good season, I felt good, like I progressed and now I am ready for Manchester.”
In the holding midfield role Schneiderlin has Michael Carrick, Daley Blind and Bastian Schweinsteiger for competition.
If Van Gaal decides to play Schneiderlin in a more advanced position, he will face competition from the likes of Ander Herrera, Juan Mata, Marouane Fellaini, Adnan Januzaj, Angel di Maria and Andreas Pereira.
But the 25-year-old is unfazed by the prospect of the fight he has on his hands to secure a first-team place.
“At a club like Man Utd, you can’t expect anything else (other than competition),” Schneiderlin said.
“We want competition. When you have competition you want to do your best, and that is how you get better.
“I wouldn’t make that step if I wasn’t ready for it.”
Like Schneiderlin, United will have to take a big step up this season if they are to challenge for the title.
The Red Devils finished fourth last year, some 17 points shy of winners Chelsea.
But having boosted the squad with the signings of Memphis Depay, Schweinsteiger and Matteo Darmian, as well as his own capture, Schneiderlin thinks United will be challenging on all fronts this term.
“The aim for a club like Manchester is to win everything,” he said.
“It’s a big step (from fourth to first) but with the players we have it is more than possible.”
The fact that United have not won anything of note since Sir Alex Ferguson left has had no impact on how Schneiderlin views his new club.
“Manchester United is Manchester United, when you look at the badge, the stadium, it’s the biggest club in the world,” he said.