Premier Kathleen Wynne and her predecessor Dalton McGuinty, as well as many members of the Liberal caucus and Toronto city council were on hand to grieve with their colleague.
Christopher Peloso, 40, was found dead by police on Monday, a day after he went missing. He also disappeared in September, but was found by cops two days later in a wooded area near train tracks.
A visibly emotional Smitherman, known for both his aggressive political style and an openness about his private life that's rare among public figures, was near tears as he spoke about his husband's battle with mental illness and breaking the news to their two young children, both under the age of six.
The pressures Peloso felt were "unbelievable and insurmountable," Smitherman said.
"He had so much strength," he told the packed crowd in a downtown community centre.
"He would never say no, he would never complain and he certainly would never really ask for help."
Peloso was a devoted stay-at-home dad to their adopted son and daughter and adored his adult biological daughter from a previous relationship, Smitherman said. He loved animals to the point of pulling over to the side of the road to rescue an injured bird.
His husband was a private person, but supported Smitherman in his political career, even pushing him to run for a federal seat in 2013 when former Liberal leader Bob Rae stepped down, he said.
"While we can focus on the glaring reality that he took his own life at a shockingly young age, you mustn't lose sight of his mark on me and our family," Smitherman said.
"We are his legacy project. I'm the better man for it."
Peloso's father Reno said he and his wife are struggling with guilt about what they could have done to stop their son from taking his own life. But the outpouring of support is helping them through it, he said.
"It's going to make it easier for us, when people come up to us and say, 'What happened?'," he said.
"It's going to be easier for us to say, 'You know what? Chris suffered from depression, he committed suicide and there's no shame in that.'"
Former Toronto mayor Barbara Hall, a close family friend, said Peloso worked hard to deal with his deep depression.
"In recent months he spoke often of the stigma and the stereotypes he felt and feared because of his illness," she said.
"Society and attitudes are changing, but not fast enough, leaving too many like Christopher defeated."
She urged the crowd to create a legacy for Peloso, where stigma surrounding mental illness is eliminated and all loved ones are supported through illness, "whatever form it takes."
Smitherman, 49, and Peloso, a former executive at chocolate company Lindt, met about 20 years ago and were married in August 2007. They later adopted two children, Michael and Kayla.
Smitherman, who was first elected to the provincial legislature in 1999, served as deputy premier, health minister and energy and infrastructure minister before stepping down in 2010 to run for Toronto mayor. He lost to Rob Ford.
Note to readers: CORRECTS day when police found Peloso's body
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