Sen. Cory Booker, and Maryland Gov. Wes Moore are also expected to take the stage before Minnesota Gov. Tim Walz's Wednesday prime-time address, according to DNC Executive Director Alex Hornbrook.
Other notable speakers tonight include figures beloved by Democrats - former President Bill Clinton and former House Speaker Nancy Pelosi.
Former Trump staffer Olivia Troye will also give remarks, Hornbrook told reporters.
Shapiro, who was among the finalist in the running to be Harris' VP pick before she ultimately chose Walz, was also at the DNC Tuesday night, representing his home state during the roll call as he proudly announced Pennsylvania's 170 delegate votes for Harris as the Democratic presidential nominee selection.
RELATED: Why did Kamala Harris choose Tim Walz over Josh Shapiro for VP? Expert weighs in
Following an interview with Harris during the vetting process for her running mate, there was a sense among Shapiro's team that the meeting did not go as well as it could have, sources familiar with the matter tell ABC News. It was also reported that after the interview, Shapiro placed a phone call to Harris' team, indicating he had reservations about leaving his job as governor, sources said.
"I want you to know I am going to continue to pour my heart and soul into serving you as your governor," Shapiro said during a rally at Temple University earlier this month.
He also touted Harris' record, contending she is "battle-tested and ready to go."
Shapiro also lauded Walz, calling him a "great patriot" and "dear friend."
RELATED: DNC Day 2 Takeaways: A double dose of Obama firepower, a doting spouse and a dance party
"I think it is fitting and I think it is special for Kamala Harris and Tim Walz to launch their campaign here in Philly, the City of Brotherly Love, and importantly they chose to launch their campaign right here in the birthplace of real freedom," he said.
During Walz speech at the Philadelphia rally, he praised Shapiro as a "visionary leader" and a "guy who cares deeply about his family, a man with compassion and vision."
"There is no one you would rather go to a Springsteen concert in Jersey with than him," Walz said as the audience shouted, "Bruce."