Sifton worked as an attorney in private practice in New York City from 1961 to 1962 and as staff counsel to the United States Senate Committee on Foreign Relations from 1962 to 1964.
From 1966 to 1969, Sifton served as an Assistant United States Attorney for the Southern District of New York.
[1] On August 16, 1977, President Jimmy Carter nominated Sifton to a seat on the United States District Court for the Eastern District of New York that had been vacated by Judge John Francis Dooling Jr. Sifton was confirmed by the United States Senate on October 12, 1977 and received his commission the same day.
[2] During his more than 30 years on the bench, he issued thousands of decisions in both civil and criminal cases.
He was survived by his wife, the artist Susan Rowland, children: Sam Sifton, the food editor of The New York Times and two other sons, Toby and John; and four grandchildren.