NBC's Lester Holt, the moderator, chose three topics for the first debate: America's direction, achieving prosperity and securing the U.S.
VP nominee and his wife reported $113,026 in income in 2015, while paying $8,956 in federal taxes.
GOP vice presidential nominee defends Trump and criticizes Clintons' wealth.
Tim Kaine and others faced disgruntled supporters of the Vermont senator on Wednesday.
"Our nation, it is just too great to put it in the hands of a slick-talking, empty-promising, self-promoting, one-man wrecking crew," Kaine said.
Democratic ticket appears together at Miami rally, drawing sharp contrasts with Trump's vision of America.
Kaine was a co-author of the bill allowing Congress to review the nuclear deal with Iran.