His Envision Peace Museum (originally Imagine Peace Museum until Yoko Ono objected) has operated since 2007 as a series of traveling exhibits.
But now, Junker and a bevy of prominent peacemakers - consultants include Ben Cohen, Ben & Jerry's co-founder, and Norwegian sociologist Johan Galtung, considered the "father of peace studies" - have begun master-planning to build a permanent home.
Over the next year, they'll plot everything from exhibits and educational offerings to fundraising and finances, said Elizabeth Tinker, the new museum's director of exhibits and programs.
They're also already scouting locations, hoping to land a spot near Independence Mall or along the Benjamin Franklin Parkway, Junker said. Still unknown is whether they'll reuse an existing structure or design something new. They're also mulling an international design competition.
The goal: To open a brick-and-mortar museum with a far-reaching online presence by 2020.
Supporters want to create a place where visitors can not only learn about peace - they'll also be able to work toward it. Preliminary plans include space and training for conflict resolution.
That's key in a city where street violence has made a mockery of our moniker, the City of Brotherly Love, Junker added.
"We have a city that's rife with violence. It wouldn't be credible for us if we didn't take stock of what's happening in our own city," Junker said. "We want to offer people resources that will help bring violence in our city down."
Philadelphia also is a city packed with museums - about 100 by an informal online count.
But the Envision Peace Museum will be like no other, Junker said.
"We have hundreds of museums [in the United States] that talk about war, but just one [Ohio's Dayton International Peace Museum] dedicated to peace," he added.
"Philadelphia has a legacy of peace going all the way back to William Penn and the treaty with the Indians," Junker said. "Peace is in our DNA. We're certainly the place with the most credibility in becoming a peace city."
On Twitter: @DanaDiFilippo