They also committed their cities to raise minimum wages, but said a national effort is needed.
"These workers deserve a guarantee that livelihoods will not be jeopardized by a change in management."
If Ellison's move survives the rest of the congressional gauntlet, it could aid tens of thousands of underpaid fast food workers at commissaries and in mini-malls on defense bases.
The convention was arguably the most open and broadly attended in the party's history. Events were live streamed and open to the press.
At the Peoples World panel on June 13 called "Working for a Living: New Challenges," workers who have been part of the Fight for 15 campaign to raise fast food wages made their voices heard.
"A city's investments should reflect the values of its taxpayers, and Walmart is consistently out of step with Portland values."
The president signed the order in a dramatic White House ceremony as Lilly Ledbetter stood beside him; it marked Equal Pay Day, the day that marks how long a woman must work into 2014 to earn the same as a man did in 2013.
A Center for American Progress report found that raising the minimum wage will not only benefit workers and the local economy, but also will reduce taxpayer costs.
The differences in commuting times for inner-city minority residents and suburban non-minorities are significant enough to affect minorities' pay and job possibilities.
They urged other politicians, notably lawmakers in Congress, to follow his lead and raise the national minimum wage.