He started his career as a journalist, little by little gaining a certain popularity, and in the late 1970s appeared in several television shows before creating its most famous show, Maurizio Costanzo Show, currently the most important and long-lasting talk show.
Costanzo's style includes subtle low-profile irony. He also wrote the screenplay for several films and the lyrics of an appreciated song, "Se telefonando" (brought to celebrity by Mina) with Ennio Morricone's music.
Costanzo's name was found in the list of adherents to the masonic lodge P2, together with Silvio Berlusconi's one; Costanzo now works for the main TV channel of the current Italian premier (Canale 5), of which he is also the artistic director. His last wife, Maria De Filippi, previously an employee of his, is now presenting several talk-shows on the same channel.
In the 1990s he was object of a spectacular attempt of murder by unknown authors: a bomb-car exploded at the passage of his car, but only two private policemen of his escort were - not seriously - injured. Certain similarities with the not failed murders of Sicilian judges Giovanni Falcone and Paolo Borsellino, together with the consideration that Costanzo had in the preceeding months sponsored media campaigns against mafia, allowed the hypothesis that it was a mafia attack. The fact has never been completely cleared. Costanzo however significantly reduced in the following years his contribution to anti-mafia campaigns. He is now the "communication-agent" (a sort of aesthetical and rettorical consultant for public appearances) of many important political leaders.