Ellis was born in 1946 and earned a Bachelor of Science degree in Physical Education from Morgan State University in 1969.

[2] Ellis' staff assignments included Deputy Chief of Staff for Operations and Plans; Assistant Deputy Chief of Staff for Personnel, Headquarters, Department of the Army; Assistant Chief of Staff, C3/J3/G3, United Nations Command/Combined Forces Command/United States Forces Korea/Eighth United States Army, South Korea; deputy director for Strategic Planning and Policy, Headquarters, United States Pacific Command, Hawaii; deputy director, Military Personnel Management, Office of the Deputy Chief of Staff for Personnel, Headquarters, Department of the Army; Force Structure Analyst and Chief, Manpower and Force Structure Division, Program Analysis and Evaluation Directorate, Office of Chief of Staff, Headquarters, Department of the Army; Staff Officer, Headquarter, United States Army Europe, Germany; Staff and Faculty, United States Military Academy, West Point; Battalion Staff Officer, 101st Airborne Division, Vietnam; and Battalion Operations Officer, 82d Airborne Division, Fort Bragg, North Carolina.

Following his retirement from the United States Army, Ellis became president and CEO of DHB Industries, a manufacturer of body armor, and has served on the boards of SRA International, the Armed Forces Benefit Association, and Universal Systems and Technology.

[6] He is married to the former Jean Williams of Baltimore, Maryland, and has two adult daughters, one of whom is an army officer.

[2] In the 2024 United States presidential election, Ellis endorsed Kamala Harris.