Biden's death marks a second tragic loss for the vice-president,whose first wife,Neilia,and 13-month-old daughter,Naomi,were killed in a car accident in 1972 when the station wagon they were driving in to go Christmas shopping was hit by a tractor-trailer. Beau Biden and his brother,Hunter,were also injured in the crash,but both survived.
A popular Democratic politician in his home state who was known to be very close to his father,Biden served two terms as Delaware's top law enforcement official before announcing last year that he would not run for a third term so he could make a bid for governor in 2016.
"What started as a thought - a very persistent thought - has now become a course of action that I wish to pursue,"he wrote in an open letter to his constituents in April 2014.
A lawyer by training,Biden joined the Delaware National Guard in 2003,serving as a major in the Judge Advocate General Corps. His unit was deployed to Iraq in 2008,while his father was running for vice-president.
In a short,emotional speech introducing his father at the 2008 Democratic National Convention in Denver,Biden recalled the tragedy that had touched his family,describing the moments after the crash.
"One of my earliest memories was being in that hospital,Dad always at our side. We,not the Senate,were all he cared about,"Biden said."He decided not to take the oath of office. He said,'Delaware can get another senator,but my boys can't get another father.'However,great men like Ted Kennedy,Mike Mansfield,Hubert Humphrey - men who had been tested themselves - convinced him to serve. So he was sworn in,in the hospital,at my bedside."
Many in Delaware expected Biden to run for his father's Senate seat after the 2008 election,but the younger Biden,who was elected attorney-general in 2006,declined,saying he was still needed in his state as he pressed ahead on a major child abuse case his agency was pursuing against a paediatrician.
"I have a duty to fulfill as attorney-general,and the immediate need to focus on a case of great consequence. And that is what I must do."
Instead,he ran for re-election in 2010,serving a second term before deciding to seek higher office.
Biden is survived by his wife,Hallie,and two children.
New York Times,Reuters