Greenhouse began her 40-year career at "The New York Times" covering state government in the paper's bureau in Albany. After completing her master's degree on a Ford Foundation fellowship, she returned to the "Times" and covered 29 sessions of the Supreme Court from 1978 to 2007, with the exception of two years during the mid-1980s during which she covered Congress. Since 1981, she has published over 2,800 articles in the "Times." She has been a regular guest on the PBS program "Washington Week".