PHILADELPHIA — Boston Mayor Marty Walsh's big speech at the Democratic National Convention in Philadelphia began like so many introductions in church basements.

"My name is Marty Walsh, and I'm an alcoholic," said the mayor, who has been in recovery for 21 years.

The mayor's roughly four-minute speech just after 7:15 p.m. on the first night of the Democratic National Convention, gave him a big stage to tell his story, and he shared with the nation his experience hitting "rock bottom" on April 23, 1995.

"I woke up with little memory of the night before and even less hope for the days to come," Walsh said.

Walsh, who was elected mayor in 2013, said his family and the labor movement were the only ones who didn't lose faith in him.

"I followed my father into the Building Trades when I was 18 years old. Labor gave my immigrant family a chance," said Walsh, whose parents are from Ireland. "The labor community got me the help I needed, and gave me a second chance. Eighteen years later I became the mayor of Boston, a city of big dreams and a big heart. As mayor I worked to give everyone a fair shot and a second chance, whether it's apprenticeships, free community college or help starting a business."

The labor community also helped elect Walsh, who was a top official at the Boston Building Trades and a state representative from Dorchester before becoming Boston's second mayor in two decades.

Walsh gave presumptive Democratic presidential nominee Hillary Clinton a ringing endorsement, calling her "the champion American workers need" and predicting she will deliver to workers the skills, jobs and child care they need to succeed.

The mayor's speech followed Congresswoman Linda Sanchez, of California, and a celebration the Hispanic Caucus. He preceded speeches by labor leaders.

Walsh also raised a labor grievance with the Republican presidential nominee, New York City developer Donald Trump. Walsh, who has parried in the press with Trump before, said Clinton believes in people "like the carpenters and electricians Donald Trump hired but then refused to pay just because he did."

Referring to his "labor family," Walsh said, "We may not have our names in gold outside any of the buildings we've worked on but our sweat, our work, our pride is on the inside of every one of them. Hillary Clinton knows that."

Also at the convention Monday, enthusiastic supporters of Sen. Bernie Sanders gave a loud reception to state Rep. Diane Russell of Portland, Maine, a Sanders delegate. Russell discussed the courage it takes to "stand up to your friends" and the "real family disagreement" among Democrats over the role of superdelegates in the presidential election process.

"In the end, I stand with my Democratic family in making sure we win this fall," Russell said. "Paul LePage is my governor. I do not need to see anyone like him become the president of this United States. Whether you support Bernie Sanders or Hillary Clinton we are all in this together and we will all have a voice in the Clinton administration."

Michael Norton contributed reporting.