Jack Layton, leader of Canada’s official Opposition and Toronto-Danforth MP, has died.

He was 61.

“We deeply regret to inform you that the Hon. Jack Layton, leader of the New Democratic Party of Canada, passed away at 4:45 a.m. today,” Layton’s wife Olivia Chow and children Sarah and Michael said in a statement released this morning. “He passed away peacefully at his home surrounded by family and loved ones.”

Layton had been battling a second bout of cancer. On July 25, he announced his fight against prostate cancer was going well but said a new, non-prostate cancer required additional treatment.

“I was deeply saddened to learn this morning of the death of Jack Layton,” Prime Minister Stephen Harper said in a statement this morning.

Layton led the NDP to a historic second-place finish in the May federal election, helping his party win 103 seats in the House of Commons.

At the July announcement less than three months later, Layton said he was taking a temporary leave of absence to focus on his treatment.

“I’m going to fight this cancer now, so I can be back to fight for families when Parliament resumes,” he said at the time.

“When I last spoke with Jack following his announcement in July, I wished him well and he told me he’d be seeing me in the House of Commons in the fall,” Harper said.

Interim Liberal Leader Bob Rae expressed his condolences and those of his party.

“Like all Canadians, Arlene and I are deeply saddened by the death of Jack Layton,” he said. “He was a friend of ours for many years, and despite our political differences his decency, good humour and extraordinary resilience earned our deep admiration.”

Layton became a fixture in Toronto politics in 1982, when he was first elected to city council.

“On the council floor, Jack Layton was a skilled debater who was well known for responding to the needs of all residents of Toronto,” Mayor Rob Ford said. “Jack was a fighter and he will be missed in Canadian politics.

“On behalf of the members of Toronto city council, I extend our deepest condolences to Jack’s wife Olivia, to son Mike Layton who serves on Toronto city council, to daughter Sarah Layton and all of his family.”

Like his father Robert, a Progressive Conservative cabinet minister in the 1980s, Layton entered the federal political fray in 2003 when he won the NDP leadership. He was elected to his Toronto-Danforth seat the next year.

“On behalf of all Canadians, I salute Jack’s contribution to public life, a contribution that will be sorely missed,” Harper said. “I know one thing: Jack gave his fight against cancer everything he had.

“Indeed, Jack never backed down from any fight.”