Flags at city hall will fly at half-mast this week to mourn the death of veteran Coun. Ron Moeser.
The longtime Scarborough councillor died of complications from lymphoma at the age of 74, his office said.
Moeser announced his illness last March. During the last city council meeting, councillors were told their Ward 44 colleague was fighting for his life.
Mayor John Tory issued a news release Tuesday saying Moeser's death will be met with great sadness at city hall.
During some 20 years on council, Moeser served as chair of the Scarborough Community Council and was instrumental in the creation of Rouge Park, Tory's statement said.
"Ron was a voice of reason and a calming presence on city council. He was fiercely dedicated to his constituents and as a resident of the Scarborough community for over 30 years, was keenly attuned to their voices," the mayor said.
Moeser served as a City of Scarborough councillor before Toronto's amalgamation. In the last election, Moeser defeated 14 rivals to hold on to his seat.
On Twitter, Coun. Josh Matlow called the news "heartbreaking," while Coun. Gary Crawford said he would miss not only his colleague, but his own city councillor.
Coun. Kristyn Wong-Tam praised Moeser's work, calling him "a passionate advocate" who will be greatly missed.
Many more councillors wished Moeser's family well. Moeser leaves behind a wife and three daughters.
There will be books of condolence at city hall and Scarborough Civic Centre as of Wednesday.