WILMINGTON, Delaware (CNN) -- Joe Biden doesn't mince words.
The Delaware senator, introduced Saturday as Democratic presidential candidate Barack Obama's running mate, has a well-earned reputation for impetuous and brutally honest remarks.
In May, Biden responded to a comment made in Israel by President Bush that compared Obama's willingness to negotiate with Iran to European appeasement of Nazi Germany before World War II.
"This is bulls**t. This is malarkey," said Biden, chairman of the Senate Foreign Relations Committee. "This is outrageous. Outrageous for the president of the United States to go to a foreign country, sit in the Knesset ... and make this kind of ridiculous statement."
Biden was criticized for describing Obama to the New York Observer as "the first mainstream African-American who is articulate and bright and clean and a nice-looking guy." Watch some of Biden's gaffes »
Biden later apologized in speeches and an appearance on "The Daily Show."
"What I was attempting to be -- but not very artfully -- was complimentary," Biden told Jon Stewart. "This is an incredible guy, c'mon! He's a phenomenon."
Biden drew a big laugh during a Democratic debate in April 2007. NBC's Brian Williams mentioned Biden's free-speaking reputation and asked the candidate whether he would have the self-discipline as president to refrain from saying too much.
Biden's complete answer: "Yes."
Biden abandoned his White House run after a poor showing in Iowa's first-in-the-nation caucuses.
The longtime Democratic senator brings years of experience that could help counter GOP arguments that an Obama administration would be inexperienced on foreign policy.
The buzz surrounding him intensified this week after he returned from a two-day trip to the Republic of Georgia after Russian troops invaded.
He ran for the 1988 Democratic presidential nomination but dropped out after charges of plagiarism in a stump speech. Rival Democratic candidate Michael Dukakis distributed a videotape that showed that Biden lifted parts of his speeches from remarks made by Neil Kinnock, then leader of Britain's Labor Party.
Biden, 65, was first elected to the Senate at age 29 in 1972. Shortly afterward, his first wife and daughter were killed in a car accident. He considered resigning but decided to continue with his political career.
He is serving his sixth term, making him Delaware's longest-serving senator. He commutes to Washington daily on Amtrak from his home near Wilmington, Delaware, according to the Almanac of American Politics.
He has a liberal to moderate voting record, the almanac indicates, and served as chairman of the powerful Judiciary Committee from 1987 to 1995. The contentious Supreme Court nomination hearings of Robert Bork and Clarence Thomas took place on Biden's watch.
Biden voted for the Iraq war resolution in October 2002 but quickly became a strident critic of the Bush administration's handling of the conflict. He strongly opposed the increased deployment of troops in 2007.
"We've tried the military surge option before, and it failed. If we try it again, it will fail again," he said in December 2006.
A Roman Catholic, Biden is married and has three children and five grandchildren. He received his undergraduate degree from the University of Delaware and got a law degree from Syracuse.
He was born in Scranton, Pennsylvania, on November 20, 1942.