News of Jack Layton's death was met with shock and sadness on Monday in Toronto, the city where the federal leader first cut his political teeth as a firebrand city councillor.

Layton died early Monday in his Toronto home after a battle with cancer. He was 61.

Layton served for 18 years on Toronto city council and Toronto Metro council.

Flags at City Hall, Metro Hall and Toronto civic centres were lowered to half-mast, and will remain lowered until the end of the day of Layton's funeral. A state funeral is planned for Saturday in Toronto.

Meanwhile, an impromptu memorial service was held at city hall where mourners wrote notes of thanks to Layton with chalk on the building's wall.

Toronto Mayor Rob Ford said he owed much to Layton who he served with on city council.

"I wouldn't be where I am without Jack Layton … No one taught me more about city hall work than Jack Layton did. I listened to every word he said. He taught me so much."

On the street outside Layton's constituency office, flowers were left for the man that many in the community knew simply as "Jack."

"Wherever you live in Canada, you've lost a friend," Torontonian Karen Harrison said outside the Dundas Street and Broadview Avenue office.

While people on the streets of Toronto were upset by the news, tributes and condolences poured in to CBC from politicians who worked and at times battled against Layton.

Two former Toronto mayors, David Miller and Mel Lastman, were among the many political figures to highlight the impact the veteran politician left both on the city and on the country.

Miller, who said he was "extremely saddened" to hear of Layton's death, noted Layton's passion for not only politics, but also for his wife Olivia Chow and his children.

"Jack had tremendous passion. He had two loves — politics and Olivia," Miller told CBC News. "He just loved Olivia. He loved his family. And they were an incredible team."

Messages of all kinds paid tribute to the NDP leader who first made his mark as a city councillor in Toronto. Canadian Press

Lastman, who also served with Layton during his time on city council, said he would remember Layton as a politician who "strongly believed in the things that he said and did, unlike many other elected officials."

"Everybody respected him. You had to," said Lastman. "Whether you were far left or far right or anything, you respected Jack. I liked Jack."

Though, Layton was born into a position of power with his family's deep political roots — his father was a cabinet minister in Brian Mulroney's government — he is probably best remembered for his tireless support of the homeless and downtrodden.

"He came from a politically powerful family and he turned that into a voice for the powerless," said Toronto councillor Pam McConnell.

City councillor Adam Vaughan, who also grew up in a political family as the son of veteran politician Colin Vaughan, remembers Layton for his keen political insight.

"He had this ability to see issues that were on the horizon for the rest of us but were right in front of him as clear as day," Vaughan said.

"He could pull together from the right, from the left, from the centre, newcomers to politics, veterans in politics, he could pull them back either for one more fight, or for a new fight or for a fight that he never expected to join and he could start to make the issues part of the political discourse."

Those in the tightly knit arts community also remembered Layton as not only as a supporter of local talent but also as a good friend.

Lorraine Segato, lead singer of Toronto band The Parachute Club, sang at Layton and Chow's wedding and remained a close friend with the couple. She later penned a song for one of his election campaigns.

Segato said people may have realized too late what a great man Layton was.

"He's a rare man and it's interesting now that so late in his life that people are really starting to get what an extraordinary person he is."