The 66-year-old is a veteran of the Vietnam War, where he served as an infantry squad leader and was awarded two purple hearts. Hagel volunteered to join the army, and the experience has influenced his thoughts on taking the country to war. If he is confirmed, he would be the first defense secretary to have seen combat as an enlisted solider. He obtained a college degree with the help of the G.I. Bill and has always advocated for services for veterans.
He's also familiar with military operations and the general culture at the upper echelons of the armed forces, specifically at the Pentagon. He currently sits on the secretary of defense's policy board.
Hagel is more likely than many conservatives to support a more rapid withdrawal of troops from Afghanistan. He criticized some of the Bush administration's Afghan war policies, and has made repeated trips to the country. He opposed both the Iraq and Afghanistan troop surges, and is not opposed to defense spending cuts.
According to the Huffington Post, "Hagel has declared that militaries are 'built to fight and win wars, not bind together failing nations.' In a radio interview this year, he spoke broadly of the need for greater diplomacy as the appropriate path in Afghanistan, noting that 'the American people want out' of the war."
3. He's had an Impact in Latin America
While much attention is being paid to Hagel's record on Israel and Iran, he has taken action on Latin American issues as well. Hagel cosponsored legislation to ease trade restrictions on Cuba. He even skipped the 2008 Republican national convention to travel to Central and South America.
Hagel has also said the prison at Guantanamo Bay in Cuba is the reason the country is losing an "image war," and that closing it could help.
As the Washington Post noted, Hagel told CNN, "It's identifiable with, for right or wrong, a part of America that people in the world believe is a power, an empire that pushes people around, we do it our way, we don't live up to our commitments to multilateral institutions."
According to the Post, Hagel criticized Defense Department leaders for not taking responsibility for issues at the prison, such as the harsh treatment of prisoners and the desecrations of the Koran.
Florida Sen. Marco Rubio (R) has some concerns about Hagel's Cuba policy, however.
As a Miami Herald blog post notes, "Florida Sen. Marco Rubio has another concern: Hagel's position on Cuba, which has lined up with others who say sanctions are 'outdated, unrealistic, irrelevant policy.'"
Hagel voted in favor of a fence along the United States-Mexico border in 2006.
He has supported free trade agreements with several Latin American countries, including Peru and Chile.
4. He Worked With Sen. Menendez on Immigration Reform
Hagel has been a proponent of immigration reform, working with Sen. Bob Menendez (D-New Jersey) on a proposal to keep immigrant families together, and he supported the comprehensive immigration reform act of 2007, which would have both increased border security and offered a path to citizenship for some undocumented workers. That bill failed.
5. He's Shifted His Position on Gay Rights
Some gay-rights group are wary of Hagel. He once referred to a gay nominee for ambassador as "openly aggressively gay," and he also supported "Don't ask, don't tell," preventing openly gay people from serving in the military.
The Log Cabin Republicans, a gay GOP group, recently published a newspaper ad opposing Hagel's potential nomination to be defense chief.
But Hagel has reportedly evolved in recent years, stating that he was in favor of ending the "Don't ask, don't tell" policy.