The Dutch youth star completed a switch to the Eagles on Thursday, joining for the full duration of the season.
Apparently, the transfer has been necessitated by his limited playing opportunities under Jose Mourinho, having made only four league appearances for the Red Devils last season.
“The manager spoke to me about coming down to join Crystal Palace and it was clear that he wanted me to be part of his squad which, as a player, gives you a great feeling straight away," Fosu-Mensah told his new club's official website.
"I must now repay that back by putting in some good performances for the club.
“I am only 19 years old and still have a lot to learn.
"Therefore, getting the opportunity to play more games on a regular basis will help my development.
"Here at Palace, I am looking forward to playing games on a regular basis and develop my game and I will listen to the management team as I am eager to learn every single day."
Fosu-Mensah joined United in 2014 after impressing for Dutch side Ajax at the AEGON Future Cup, and under Louis van Gaal in 2015-16, had eight topflight outings in his first year of Premier League football.
He is currently on the radar of Ghana who are keen to persuade him into a nationality switch after playing for the Dutch at youth level.