On his 17th birthday, the Northern Ireland youth international put pen to paper this week.
Advertisement
Advertisement
Kerr joined the Hammers last year from Glentoran.
"It's a really proud moment for me and my family," he told the club's website. "It's obviously something I've wanted to do and have been working towards for a while now, so it's great to see that dream become a reality and sign professional.
“My last 12 months have been really good," he continued. "Hopefully that's something I can keep building on to make sure the next 12 months are even better.