"I want to thank the people of Delaware and I'll be going back to the Senate as chairman of the Senate Foreign Relations Committee," he said.
The veteran lawmaker received less than 1 percent of the vote despite a spirited campaign in which he emphasized his international policy credentials and long career in public service.
Thursday night was a case of deja vu for Biden, who sought the Democratic presidential nomination 20 years ago - in 1988 - but left the race before the Iowa caucuses that year amid accusations that he had plagiarized from speeches by a British Labor Party leader.
This time, Biden campaigned extensively in Iowa, focusing on his plan for ending the Iraq war and the broad foreign policy experience he gained from more than 30 years in the Senate. Biden also noted the many time his rivals acknowledged agreeing with him.
His advisers had hoped for a fourth-place finish and thought even third place was possible.
Biden, 65, went to the Senate in 1973 after winning a race few expected him to. He was only 29, but turned 30 - the minimum age for service in the Senate - shortly thereafter.
In the years since, he has overcome personal tragedy and near death experiences.
Five weeks after his election, a station wagon driven by his wife, Neilia, was broadsided by a tractor-trailer in Delaware as she drove home with a family Christmas tree. She and the couple's 18-month-old daughter, Naomi, were killed. Their two young sons, Beau and Hunter, were seriously injured.
Biden said at first that he no longer wanted the job he had just won, but Senate leaders persuaded him to assume his seat. He was sworn in from the hospital bedside of one his sons. It remains his habit not to work on Dec. 18.
In 1977, Biden married Jill Tracy Jacobs. They have a daughter, Ashley. Both of his sons are lawyers, and the elder son, Beau, was elected state attorney general of Delaware in November.
Biden himself had a close brush with death in February 1988, when he was hospitalized for two brain aneurysms. It was seven months before he could return to the Senate.
Biden voted to authorize the war in Iraq, but since has become one of Congress' most vocal critics of the Bush administration's handling of the war. He was the only Democrat in the presidential race who advocated partitioning Iraq as a means of ending the war and U.S. military involvement there.
He was chairman of the Senate Judiciary Committee from 1987 to 1995, and presided over two of the most contentious Supreme Court confirmation hearings, for Robert Bork in 1987 and for Clarence Thomas in 1991.
During his tenure on the Judiciary Committee, Biden wrote several anti-drug laws and the landmark Violence against Women Act of 2000, which contains a broad array of measures to combat domestic violence and gender-based crimes. Part of the law was later struck down as unconstitutional.
Biden is known for a tell-it-like-it-is speaking style that resonates with ordinary Americans, with a quick wit and colorful phrasings that have made him a sought-after guest for television and radio interviews. But he's also developed a reputation as a long-winded publicity hound.
In one Democratic debate last year, Biden drew laughs when, commenting on Republican candidate Rudy Giuliani's foreign policy experience, he said the former New York mayor's message amounted to "a noun, a verb and 9/11."
That Biden is regarded as a loquacious orator underscores how far he's come from his roots in New Castle, Del., where he was teased by his classmates because he stuttered.