Born in Hot Springs, Arkansas, Moscowitz received a Bachelor of Laws from New York University School of Law in 1906.

He was in private practice of law in Brooklyn, New York from 1907 to 1925.

He was a special deputy state attorney general of New York from 1909 to 1910 and from 1922 to 1925.

[1] Moscowitz was nominated by President Calvin Coolidge on December 16, 1925, to a seat on the United States District Court for the Eastern District of New York vacated by Judge Edwin Louis Garvin.

He was confirmed by the United States Senate on December 21, 1925, and received his commission the same day.