The 24-year-old joins from Limavady United after impressing on trial for the Bannsiders during recent pre-season matches.
Brown, who was also previously on the books at Derry City and Tobermore United, has signed a two-year deal at The Showgrounds.
Bannsiders boss Kearney revealed Brown has been on his radar for quite some time.
“We have played Limavady quite a few times and he has always been a player who has caught my eye,” he told the club website.
“He scored over twenty goals for Limavady last season and his rate of progress has been very good.
“Dean has worked extremely hard since joining us in pre-season and is hungry to do well.
“He is a quick learner and it’s up to him now to grab this opportunity.”