First elected to the US Senate when Barack Obama was just 11, Joe Biden brings a wealth of experience to the Democratic ticket.
Born into a working-class Catholic family, the 65-year-old also has the common touch that critics say his presidential partner lacks.
With his modest background and outspokenness, he looks perfectly placed to attract support from blue-collar Americans – a key part of the electorate.
But the choice of the veteran Delaware Senator as Obama’s running mate does carry some risks.
“On the minus side, Biden has bombed out twice as a presidential candidate,” said political analyst Allan Lichtman.
“The first time he ran, there were accusations of plagiarism. He can be gaffe prone in the same way that John McCain is gaffe prone.”
Having pulled out of this year’s race for the Democratic presidential nomination, selection as Obama’s running-mate was a major success for Biden. Yet, at a rally in New Hampshire in September, he raised eyebrows by suggesting that Hillary Clinton may have been a better choice.
“She is qualified to be President of the United Sates of America,” he declared.
“She is easily qualified to be Vice President of the United States of America and, quite frankly, it might have been a better pick than me. But she is first-rate. I mean that sincerely. She is first-rate.”
For supporters however, Biden’s background as a foreign policy big-hitter outweighs any amount of curious comments. He has chaired the influential Senate Foreign Relations Committee three times. Biden’s website says his leadership was “widely hailed for helping to bring stability and peace to the Balkans.”
But the elder statesman has also known personal tragedy. Now remarried, he lost his first wife and baby daughter in a car crash in 1972. Devastated, Biden thought of abandoning a political career that may yet take him to the vice presidency of the United States.