Gen Julius Waweru Karangi joined Kenya Air Force in 1973 and after Cadet training in UK , he was commissioned as an officer in 1974. After qualifying as a Flight Navigator in October 1975 in the Royal Air Force in England , he was posted to Flying Wing Kenya Air Force where he worked as a Navigator.

Gen Julius Waweru Karangi has been trained in Kenya , United Kingdom (UK), India and United States
He has served as an officer in charge of the management of the American Military Aid to Kenya , Officer in charge of the Research Department in the Defence Headquarters, Commander of an Air Defence Battalion in Kenya Air Force, Liaison officer in Sarajevo (Bosnia), Senior Military Liaison Officer in Belgrade (Serbia), Senior Military Observer in Belgrade and Croatia all with the United Nations as a peacekeeper in 1992/93, Staff Officer in Kenya Air Force Headquarters in charge of Administration, Personnel and Logistics, Iinstructor in Defence Staff College and the Armed Forces Training College, Lanet.

In 1995, he was appointed the Commander of a Kenya Air Force Base, Moi Air Base. In 1997, he was appointed the Commander of the Kenya Air Force Logistics Command. In 1998, he was posted to Defence Headquarters and appointed Chief Procurement of the Kenya Defence Forces. In May 1999, he was appointed to a senior position of Assistant Chief of Defence Forces at Defence Headquarters in charge of Training, Doctrine and Procurement for the Kenya Defence Forces.

Gen Karangi was appointed Commandant Defence Staff College , Karen where he worked between Dec 2000-Nov 2003 in the rank of Major General , after which he was appointed Commander Kenya Air Force and served from Nov 2003 to 10th Aug 2005. On 10th August 2005, he was promoted to the rank of Lieutenant General and appointed Vice Chief of Defence Forces, Defence Headquarters.On 13th July 2011 he was promoted to the rank of General and appointed the new Chief of Defence Forces(CDF), his current position.

General Karangi is married to Mrs. Mary Karangi and they are blessed with three children, two daughters and a son.