Hunter Biden (L), with his father Joe Biden (C) and late brother Beau Biden (R) at the 2009 inauguration of President Barack Obama
Washington (AFP) - Unlike his father Joe or late brother Beau, Hunter Biden never sought the attention that comes with running for political office.
But the Congressional impeachment inquiry into the actions of US President Donald Trump has put a harsh spotlight on the sometimes troubled life of the former vice president's youngest son.
Robert Hunter Biden, 49, has publicly acknowledged battles with addiction, stints in rehab, extramarital affairs and having exercised "poor judgment" at times.
"I've been through some stuff in my life," he said in an interview with ABC News in October. "I have fallen and I've gotten up."
Biden provided a candid account of his struggles with drugs and alcohol, and his marital woes, in an extensive profile published in The New Yorker magazine in July.
At perhaps his lowest point -- about a year after the 2015 death of his brother -- he said he had a gun put to his head while buying crack cocaine in a homeless encampment in Los Angeles.
But it is Biden's business career -- not his personal life -- that has drawn him into the impeachment probe, specifically, his position on the board of Ukrainian gas company Burisma while his father was vice president.
Trump is threatened with impeachment for asking Ukrainian President Volodymyr Zelensky to investigate Biden and his father, who might end up being Trump's Democratic opponent in next year's election.
Trump and his Republican backers have sought to shift the focus away from the president's conduct and on to Biden's business dealings.
Republicans accuse him of trading on the family name to earn a lucrative position on the Burisma board and to raise money in China for an investment fund.
- 'Conflict of interest' -
Biden served on the Burisma board from 2014 to 2019 and was reportedly paid $50,000 a month.
The Ukrainian firm has been the target of corruption accusations, but Biden has not been personally accused of criminal wrongdoing.
Republicans have argued though that he only got the position because of his family name.
Biden does not entirely disagree but cites his credentials in his defense.
"I don't think that there's a lot of things that would have happened in my life if my last name wasn't Biden," he told ABC News.
"I was vice chairman of the board of Amtrak for five years," he added.
"I was the chairman of the board of the UN World Food Program. I was a lawyer for Boies Schiller Flexner, one of the most prestigious law firms in the world."
He does acknowledge, however, that taking the Burisma position may have been a mistake.
"In retrospect, look, I think that it was poor judgment on my part," he said. "I gave a hook to some very unethical people to act in illegal ways to try to do some harm to my father."
While Biden may have second thoughts now, others expressed their concerns to the vice president's office at the time.
George Kent, the deputy assistant secretary of state for European and Eurasian affairs, said he raised the issue in February 2015, when he was serving at the US embassy in Kiev.
"I raised my concern that Hunter Biden's status as a board member would create the perception of a conflict of interest," Kent told the impeachment hearings in the House of Representatives.
- 'Alice in Wonderland' -
While Democrats have managed so far to shield Biden from Republican efforts to have him appear as a witness, his life has never been far from the headlines.
As a toddler, Biden lost his mother and sister in a 1972 car crash that left him and Beau badly injured.
The accident came just weeks after Joe Biden had won election to the Senate from the tiny eastern state of Delaware.
Both boys recovered from their injuries and Beau eventually followed his father into politics, becoming the attorney general of Delaware and contemplating a run for governor before dying of brain cancer in May 2015 at the age of 46.
Biden earned a law degree from prestigious Yale University and embarked upon a career as a lawyer and lobbyist.
Following Beau's death, Biden became briefly romantically involved with his brother's widow, Hallie Olivere, and his wife of nearly 25 years, Kathleen Buhle, filed for divorce.
As for his current situation, Biden says it is all a bit surreal.
"It feels to me like living in some kind of, you know, 'Alice in Wonderland,'" he said.
"The president's the Cheshire Cat asking you questions about crazy things that don't bear any resemblance to the reality of anything that has to do with me."