Michelle Obama drew loud applause from the audience when she referred to her husband's Nobel Peace Prize.
"You were doing the people's work," she said of Barack Obama.
"Rescuing our economy, expanding health care, ending a war, ordering the bin Laden raid, saving an auto industry, winning a peace prize," she said, pausing as the audience cheered.
Obama won the prize in 2009.
Trump has frequently made known his desire to win the Nobel Peace Prize. He has not won the award.