Chicago labor icon Edward Sadlowski died Sunday, his daughter said. He was 79.

The former United Steel Workers of America leader fought to bring democratic reform to labor unions. He was elected president of Local 65 at the age of 26, and he narrowly lost a campaign for international president.

Ald. Susan Sadlowski Garza (10th) said the outpouring of support for her family that followed his death Sunday has been overwhelming.

“I knew my dad touched a lot of people, but the stories and everything that I’ve heard today is just very heartwarming to me,” she said. “My dad was a true working-class hero.”

The alderman recalled how her father used to rouse her out of bed to walk picket lines and deliver donuts at the age of 6.

“Who can not take something from a 6-year-old kid?” she said.

Mayor Rahm Emanuel said in a statement that Sadlowski “rose from working as a machinist’s apprentice on Chicago’s southeast side, to being elected shop steward of his steel mill, to leading the largest local Steelworkers union in America.”

“He served bravely in the Army, and fought passionately for the rights of workers in Chicago and across America,” Emanuel said. “Our thoughts and prayers are with his daughter Alderman Susan Sadlowski Garza, the entire Sadlowski family, and Ed’s brothers and sisters in the labor movement on this difficult day.”

A private memorial will take place in Florida, where Mr. Sadlowski had retired. A Chicago-area service is being planned later, said Ismael Cuevas, chief of staff for Sadlowski Garza.