Oyakhilome became Chief Superintendent of Police, Criminal Investigation Division of the Rivers State Police, Port Harcourt. He served in Grenada. He became military governor of Rivers State in January 1984 after the military overthrow of the Nigerian Second Republic. On 19 April 1984, Oyakhilome signed the edict establishing the Rivers State School of Basic Studies, later to become the Rivers State College of Arts and Science in Port Harcourt. As governor he successfully increased agricultural output in the state. His "School to Land" program made headline news, but was later abandoned as enthusiasm waned. He was redeployed on 26 August 1986, replaced by Colonel Anthony Ukpo. Oyakhilome was Chairman of the National Drug Law Enforcement Agency . He was dismissed after being accused of having a relationship with Jennifer Madike, a Lagos business woman and socialite who had been arrested for drugs-related offences. Prior to her arrest, she had a successful career with her company "Biofrika Ventures" and through real estate, and was a constant subject of the gossip columns. She was arrested on a charge of collecting US$80,000 from three men, claiming she was going to give the money to Oyakhilome to secure the release of two suspected drug dealers. The United States later unsuccessfully applied for extradition of one of the dealers on charges of heroin smuggling.
Later career
After leaving the NDLEA, Oyakhilome became head of his own private law firm. He represented retired police officers at the National Political Reform Conference in 2005. In 2009 he was Vice-Chairman of the Association of Retired Police Officers of Nigeria. He was an investor in EBS Nigeria, a previously unknown firm that in June 2006 gained a major contract for supply of anti-retroviral drugs from the Federal Ministry of Health. Other directors included retired military officers Brigadier General Abu Ahmadu and Major General David Jemibewon. In 2008, as a consultant to the National Universities Commission he gave a list of 33 "universities" that were operating illegally in Nigeria since they had not been licensed by the Federal Government and NUC.
