Previously she was an attorney at the Orleans Public Defenders, where she represented juvenile clients being prosecuted as adults and adult clients charged with serious felonies. Angelson has also worked at the Neighborhood Defender Service of Harlem and in the office of then-Senator Joseph R. Biden on the Crime and Drugs Subcommittee of the Senate Judiciary Committee. She later served as a clerk for the Honorable Robert W. Sweet of the Southern District of New York. Angelson received a B.A. from Yale University and a J.D. from New York University.