According to The Hollywood Reporter, the 57-year-old actor will play fiery Pastor Ramon Cruz in the music drama, which will arrive on Netflix in 2016.
The 13-episode series will follow a "rag-tag crew" of South Bronx teenagers who change the music scene of the '70s.
Luhrmann said: "Continuing the high quality of our acting company in The Get Down, we're very pleased to announce that Giancarlo Esposito will be joining us in the role of Pastor Ramon Cruz.
"Giancarlo has played such a variety of roles and he's a tremendous asset to our production."
He joins previously announced cast members Jaden Smith, Jimmy Smits, Herizen Guardiola, Shameik Moore, TJ Brown, Justice Smith and Skylan Brooks in the drama.