The first presidential debate between US Vice President Kamala Harris and former President Donald Trump took place in Philadelphia on September 10, 2024, lasting for one hour and 45 minutes. This debate is viewed as one of the most significant national discussions in recent history, focusing on how effectively each candidate could appeal to swing voters while maintaining confidence among their supporters.

During the debate, Harris was questioned about the domestic economy, where she proposed increasing the child tax credit and providing tax deductions for startup businesses. She criticized Trump, claiming he left the Biden-Harris administration with the highest unemployment rates since the Great Depression and pointing to the January 6 Capitol riots as a severe attack on democracy. In contrast, Trump supported the idea of imposing substantial tariffs and accused undocumented immigrants of taking jobs from Black and Hispanic Americans. Harris responded by describing Trump's benefit of trade wars and dismissed his tariff proposals as a tax on the American public.

The candidates also exchanged views on foreign policy, including the ongoing conflicts in Ukraine and Gaza. Trump expressed a desire for the Ukraine war to conclude but avoided taking a clear stance on whether he wanted Ukraine to prevail against Russia. Meanwhile, Harris accused Trump of being willing to withdraw support for Ukraine to appease Russian President Vladimir Putin. On the topic of the Israeli-Palestinian conflict, Trump accused Harris of harboring animosity toward both Israel and the Arab population, while Harris vehemently denied these claims and labeled Trump as "weak" in his foreign policy stance.

Following the debate, Trump claimed it was his best performance yet, but a New York Times analysis noted that he seemed to be on the defensive throughout the night. A post-debate poll indicated that many undecided swing-state voters felt Harris had outperformed Trump, a sentiment echoed by registered voters who watched the debate according to a CNN poll. Additionally, in a show of support for Harris, pop-culture icon Taylor Swift endorsed her shortly after the debate concluded.