His first acting experience in film was a small role in a Giulio Base's feature film featuring
Shelley Winters and
Vittorio Gassman, shot in the "
Cinecittà" film studio in Rome. He guest starred in an episode of the Italian television series
Medicina generale in 2010. He appeared in several television shows in 2013, including
Beauty & the Beast and
Copper, in which he starred in three episodes. Gianniotti played a recurring role as Lord Julien in the first season of
Reign. In 2019, Gianniotti was one of the recipients of the Top 25 Canadian Immigrant Awards presented by
Canadian Immigrant magazine. In 2021, Gianniotti won the
Tell-Tale TV Award for Favorite Actor in a Network Drama Series for his role on ''
Grey's Anatomy''. In 2024, Gianniotti starred as Elia in the
Netflix Italian series
Deceitful Love. Since 2024, he has starred as Detective Cole Ellis in the series
Wild Cards. ==Personal life==