Christopher James Christie (born September 6, 1962) is an American politician, former federal prosecutor, and political commentator who served as the 55th Governor of New Jersey from 2010 to 2018. During his governorship, he chaired the Opioid and Drug Abuse Commission in 2017. Christie became an ABC News contributor in 2018 after leaving office. Christie was born in Newark and raised in Livingston.
Despite having criticized Donald Trump prior to leaving the race, he endorsed Trump on February 26, 2016. On May 9, 2016, Trump named Christie to head up a transition team in the event of a Trump presidency. He soon emerged as a major power with the Trump campaign. Trump considered Christie as a potential vice-presidential running mate, and was on the shortlist alongside former Speaker of the House Newt Gingrich and Indiana Governor Mike Pence. Trump passed over Christie and selected Pence. In September 2016, Christie acknowledged that the Fort Lee lane closure scandal, also known as Bridgegate, was a factor in his being denied the nomination. Trump had said earlier that Christie knew about the closures, which Christie denies. Following the release of Trump's tape-recorded comments on an Access Hollywood bus, Christie called Trump's comments "completely indefensible", but also added "I don't think it's the only way you should make a judgment." After calls for his impeachment as Governor and felony convictions in U.S. federal court for high-ranking members of his staff in the Bridgegate scandal, Christie was dropped by Trump as leader of the transition team, in favor of Pence. On the same day, Christie's close associates Richard Bagger and Bill Palatucci were both removed by Trump from the transition team. Former Congressman Mike Rogers, a national security expert on the Trump transition team, was additionally another close associate of Chris Christie who was also removed a few days after Christie's departure. Christie was being considered for a role in the Trump administration, but has said he will serve out his term as governor, which ended in January 2018. On December 11, it was reported that Christie turned down offers to become Secretary of Homeland Security and Secretary of Veterans Affairs, because he wanted to be Attorney General. In February 2017, it was reported that Christie turned down an offer to act as Secretary of Labor, saying he would finish his term as governor after which he would move to the private sector.

Q: what did he do on the trump campaign?
A: he endorsed Trump on February 26, 2016.

Q: what were his responsibiliites?
A: unknown
what was his administration role?
head up a transition team in the event of a Trump presidency. Christie was being considered for a role in the Trump administration, but has said he will serve out his term as governor, which ended in January 2018. it was reported that Christie turned down offers to become Secretary of Homeland Security and Secretary of Veterans Affairs, named Christie to head up a transition team in the event of a Trump presidency. He soon emerged as a major power with the Trump campaign. Christie was being considered for a role in the Trump administration, but has said he will serve out his term as governor,
Christie was being considered for a role in the Trump administration, but has said he will serve out his term as governor,