Born in Chevy Chase, Maryland, Northrop received a Bachelor of Laws from George Washington University Law School in 1937.

He was in private practice in Rockville, Maryland and Washington, D.C. from 1945 to 1961.

He was a member of the Maryland Senate from 1954 to 1961, serving as Majority Leader from 1958 to 1961.

[1] Northrop was nominated by President John F. Kennedy on August 23, 1961, to the United States District Court for the District of Maryland, to a new seat created by 75 Stat.

Northrop served in senior status until his death on August 12, 2003, in Sandy Spring, Maryland.