Van Gaal was officially unveiled as United's new manager at Old Trafford on Thursday and the Dutchman emphasised that he was fully appraised of the extra responsibilities that now rested on his shoulders.
United leave for their pre-season tour of the United States on Friday and there is a possibility of further exhibition friendly matches in lieu of European football next season to generate extra revenue.
"This club is also guided in the commercial way and we have to fulfil that also," Van Gaal said.
"That is not always possible, to fulfil the commercial expectations or the football expectations. That is my biggest challenge after two weeks.
"Maybe it will change after the US tour. I don't know, but I don't think so. This is the biggest club because it is known worldwide.
"It's a club that is well known all over the world. When I was in China, or now in Brazil people are talking about Manchester United. That's the difference.
"There is a lot of expectation, but also a great challenge because of that and therefore I have chosen this club."
Van Gaal confirmed he will not hesitate to seek the advice of former United manager Sir Alex Ferguson, with whom he already has a solid relationship and a great admiration.
"Sir Alex has a strong philosophy. He was always confirming that because he won a lot of titles with Manchester United," Van Gaal said. "I think he has a good philosophy. I hope I can do that and start with philosophy.
"He called me to congratulate me and when we have spoken about a coffee to drink, or to eat. We were always invited to the elite forum of UEFA. We always had a glass of wine.
"So we know each other very well and I shall drink coffee and drink wine with him. Maybe the better wine I can imagine!"
Van Gaal insisted that his initial remit at Old Trafford will be to make United's first team successful rather than to conduct a root and branch review of the whole set-up.
"The main project is the first team," he said. "The first team is more short-term than the youth education which is long-term.
"The first two years we have to separate them. Because now I need all my knowledge to transfer my philosophy into this selection.
"You have to give me time to do that. Not only you, but the chief executive and the owners."
You can watch the whole of Louis Van Gaal's news conference right now On Demand