Brooks, 17, has been playing senior football for Concord in the Isthmian League North Division.
The midfielder told whufc.com: "It's surreal. I feel incredible. It’s a moment you always dream of, and to come to a Club like West Ham United - I couldn’t ask for anything better.
“It’s been a bit different for me over the last few weeks because I haven't been in a club’s academy before, and have been playing men's football, so it was different being in a full-time environment, but I’ve settled in nicely and have enjoyed every single bit of it.
“The pathway for young players at West Ham is clear, and when you see that pathway, it gives you a real character and something to really go for as well. That was definitely one of the pushing factors as to why I chose to continue my development with West Ham United, as was having the opportunity to work with the coaches, who really want to help develop me as a player.
“I'm a competitive defensive or box-to-box midfielder and can break up play, find passes and score a few goals, too!
“It’s a Club that has a history of giving young players opportunities, and hopefully I can be part of the future.”