Senator John Edwards hailed John Kerry as a combat-tested leader ready to protect the country and help middle- and working-class Americans.
Mr. Edwards made his remarks addressing the Democratic national convention, which is set to formally nominate Mr. Kerry as the party's candidate for president.
The North Carolina senator gave examples of how Mr. Kerry saved fellow sailors' lives in the Vietnam War. He described Mr. Kerry as a man who is prepared to keep America safe and make it more respected abroad.
Mr. Edwards, the party's designated vice-presidential candidate, also vowed that he and Mr. Kerry would raise the minimum wage and penalize companies that send jobs overseas.
After his speech, Mr. Kerry's formal nomination begins, with delegates declaring their support in the traditional "roll call" of U.S. states and territories. Mr. Kerry will give his acceptance speech late on Thursday.
Earlier Mr. Kerry was endorsed by retired General John Shalikashvili, former head of the U.S. Joint Chiefs of Staff. Democrats have been promoting Mr. Kerry's military record as part of an effort to convince voters he can protect the nation's security.
Other speakers Wednesday renewed the party's attacks on President Bush. Former U.N ambassador Bill Richardson said that while U.S. military power has never been greater, international respect for the nation is at an all-time low.
Longtime African-American leader Jesse Jackson said it was time to bring U.S. troops home and send Mr. Bush back to Texas.