Moore was already in custody on unrelated charges dating back to March when he was charged Wednesday morning and taken to court where he was denied bail, the Toronto Sun said.
Detectives alleged the four homicides were premeditated, so first-degree murder charges were filed, along with such other counts as drive-by shootings, robbing a jewelry store and weapons offenses, the report said.
The killings began in September of last year, police said.
Moore's lawyer, Cheryl Robb, told the Star he called her to tell her about the newest charges and laughed on the telephone.
It was the second Canadian arrest for multiple homicides this week.
Monday, the Royal Canadian Mounted Police announced they had upgraded charges against 21-year-old Cody Legebokoff in British Columbia. He's accused of killing four women since 2009 and was described as a possible serial killer who acted alone, police said.
Aaron Carter is still in love with Hilary Duff
Ray Liotta sues skin care company over use of likeness