Leonardo DaCosta Mangum was born in the District of Columbia on 23 August 1947 He was the eldest child of the late Aaron G. Mangum and the late Inez Harris. He returned to be with his heavenly father on August 8, 2024.

Leo was raised in the District of Columbia and Montgomery County, MD. He graduated from Northwood High School in Montgomery County, MD, and attended the University of Maryland, Eastern Shore.

He joined The United States Air Force in 1967. He completed four years before moving on to The Montgomery County Police Department in 1972, where he was the 7th African American Officer hired by Montgomery County and served for 21 years. After retiring from the Police Department, he bartended at The Police Association and the American Legion Post 41. He held his last position with the City of Takoma Park Police Department as the Property Evidence Manager for 17 years.

Leo will always be remembered as a comedian, fun-loving, life-of-the-party who would help anyone in need. He loved his daughter and grandchildren unconditionally. He loved cars and enjoyed racing at 75 & 80 and has a collection of trophies from those events. In addition to cars, he loved the Temptation's music, especially the songs “My Girl” and “Aint too proud to beg.”

Leo was preceded in death by his parents, Aaron G. Mangum and Inez Harris, his wife, Noel M. Mangum, and his brother, Michael D. Mangum. He leaves to cherish his memories: his Daughter Michelle Anderson, two grandsons, Jordan E. Anderson and Jayden D. Lawson, and one niece, Danielle C. Mangum, and a host of relatives and friends.