Fazakerley, who has played international cricket for Guernsey, has been part of the county's academy.
"Will has had a really good season with the academy and the Second XI," chief executive Wasim Khan said.
"He has impressed us greatly with the progress he has made and it is great he is signing his first professional contract with Leicestershire."
Fazakerley's last international match was the annual clash between his home island of Guernsey and their Channel Island rivals Jersey, which they lost by 49 runs.
"I've only been there for two months and I didn't think I'd made a big enough impression there, but obviously they seem pretty happy," Fazakerly told BBC Radio Guernsey.
"I was planning to have another year in the academy, which is why I was so surprised when they offered me this deal, but obviously I won't complain.
"This is just the start, I want to have a long and successful career in cricket. I want to play as much first-class cricket as possible."
Leicestershire have handed 17-year-old Will Fazakerley a 12-month first professional contract.