The Colombian has struggled for fitness since moving from Monaco, though he has scored in his previous two Premier League starts - against Everton in October and Aston Villa at the weekend.
Falcao was prolific in spells at Porto, Atletico Madrid and Monaco, and Van Gaal believes he can replicate that form at Old Trafford, with the help of his colleagues.
"Falcao is also dependable on his team-mates," Van Gaal told reporters. "He can be in great form, but the team has to be in great form. That allows Falcao to show his qualities.
"When the cross is not coming from Ashley Young, then he cannot show what he has done in the last match [at Villa]."
Key to United's recent revival - winning six of their last seven games - has been the performances of captain Wayne Rooney - dropped into a creative midfield role.
Rooney has six goals and three assists to his name this term, and Van Gaal is delighted with the England skipper's ability to provide from various roles.
The Dutchman added: "He is a player who can play in different positions and I'm happy with that because I like multifunctional players.
"I can use him as a midfielder but also as a striker and attacking midfielder. He has the ability to run from box to box."