Sullivan was close with former Secretary of State Clinton, working on the former first lady's 2008 presidential campaign as a top adviser. At the State Department, he replaced Anne-Marie Slaughter as the Director of Policy Planning after she returned to Princeton University.

Sullivan also worked as an adviser to Sen. Amy KlobucharAmy Jean KlobucharOvernight Health Care: Trump eases rules on insurance outside ObamaCare | HHS office on religious rights gets 300 complaints in a month | GOP chair eyes opioid bill vote by Memorial Day Overnight Regulation: Trump to take steps to ban bump stocks | Trump eases rules on insurance sold outside of ObamaCare | FCC to officially rescind net neutrality Thursday | Obama EPA chief: Reg rollback won't stand Dems seek reversal of nursing home regulatory rollback MORE (D-Minn.) and is a graduate of Yale and Oxford.