He attended Saint Catherine"s Academy (now Saint Pius School), and graduated from Douglass High School in 1941. After the war he graduated from Howard University where he received his Bachelor of Arts in 1947. Hargrove graduated from the University of Maryland School of Law in 1950 and was admitted to the bar the same year.
When he was six months old, the family moved to Baltimore, Maryland. After high school, he entered Morgan State College in Baltimore. His studies were interrupted by World World War II when he joined the military service.
In 1957 he became the first African-American to be appointed assistant United States. Attorney for the District of Maryland, serving in that capacity for five years.
In 1967, Hargrove was elected as a delegate to the Maryland Constitutional Convention in Annapolis. In 1962, he was appointed Judge of the old People"s Court, where he served for a brief time before losing an election for the position.
The next year he and Joseph C. Howard, Senior formed the law firm of Howard and Hargrove, where he practiced law until 1968. In 1968 he was appointed Judge of the old Municipal Court of Baltimore City.
The old Municipal Court became the District Court of Maryland for Baltimore City in 1971, at which time he was named the first Administrative Judge for the newly formed District Court.
In 1974, he was appointed Associate Judge of the Supreme Bench of Baltimore City (now the Circuit Court for Baltimore City), where he served until 1984. In 1984, after being nominated and confirmed by the United States Senate, he was appointed by President Ronald Reagan as Judge of the United States District Court for the District of Maryland, a position he held from 1984 until his death in 1997. The newest of the Baltimore City District Courthouses is the Hargrove, Senior
Building, located at 700 East. Patapsco Avenue in southern Baltimore City.
Ground for this new courthouse was broken in 2001, and it is named in honor of the late Judge Hargrove, Senior, who died April 1, 1997.