He studied theater at Humber College and made his acting debut in the Italian television series Medicina Generale in 2010.

[2] He divides his time between Toronto and Rome, working in Canadian and Italian stage, films and television.

[3] He attended high school at Cardinal Carter Academy for the Arts in Toronto, then graduated from Humber College's Theatre Program.

He starred as Freddy in the television series Selfie (2014), and later acted in the made-for-TV drama film The Secret Life of Marilyn Monroe.

[6] In 2021, Gianniotti won the Tell-Tale TV Award for Favorite Actor in a Network Drama Series for his role on Grey's Anatomy.