He served as a law clerk for Judge Caleb Merrill Wright of the United States District Court for the District of Delaware from 1960 to 1961 and as a law clerk for Judge Thurgood Marshall of the United States Court of Appeals for the Second Circuit from 1961 to 1962.

He was a consultant to the Subcommittee on Separation of Powers of the United States Senate Committee on the Judiciary from 1968 to 1972.

[2][3] Winter advocated for limited government involvement in business matters.

[4] President Ronald Reagan nominated Winter on November 18, 1981, to a seat on the United States Court of Appeals for the Second Circuit vacated by Judge Walter R. Mansfield.

[3] From 2003 to 2010, Winter also served as one of the three judges on the United States Foreign Intelligence Surveillance Court of Review.