Joe Biden, 76, served nearly seven terms as a U.S. senator from Delaware before becoming vice president in the Barack Obama administration from 2009 to 2017.
Biden has run for president twice before. He is known for his homespun personality and his ability to connect with working-class voters. His campaign focuses on foreign policy and strengthening economic protections for low-income workers.
In 2017, Obama awarded Biden the Presidential Medal of Freedom for his lifetime of public service.