The 21-year-old had a two-week trial with the Phobians after he opted not to extend his stay in Cape Coast.
"It's true that I've signed for Hearts of Oak after they met with my counsel on Monday and I'm delighted with the opportunity," Esso told Goal.
"It's a big opportunity and another platform to showcase my talent to the entire country and the world at large. I believe things will be successful here looking at the kind of players I am coming to play with and the ambitions of the club as well.
"I thank everyone at Ebusua Dwarfs for the opportunity they gave and the support I enjoyed while I was with them. It was a great moment and I'm grateful," he added.
Esso made 25 league appearances for Dwarfs last season and scored nine goals, as well as making one assist to help the club finish fourth.