Rosato’s death was confirmed by his former agent, Larry Goldhar.
The Italian-born comic actor joined Martin Short and Robin Duke as the only three performers to have been cast members of both “Saturday Night Live” and “SCTV,” the classic homegrown comedy show that was spun out of Second City shortly after “SNL” launched in the mid-1970s.
One of his most memorable “SCTV” characters was Marcello, a clumsy TV chef whose “Cooking with Marcello” lessons always ended up in a kitchen disaster.
Rosato was a TV regular, with appearances on shows including “Due South,” “Street Legal,” “L.A. Law,” “Lonesome Dove,” and “RoboCop,” and the Canadian cable movie “Kissinger and Nixon.”
He was also the voice of Luigi in a pair of “Super Marios Bros.” TV series.
Rosato ran into legal trouble in later years.
In 2007, he was found guilty of criminally harassing his wife. He was diagnosed with Capgras syndrome, a condition that caused him to believe his wife and young daughter had been replaced by impostors.
Rosato spent nearly four years in custody, with time in jail and confinement in a psychiatric hospital.