Oliver graduated from Auburn, becoming an engineer with the State Road Department, returning to Pensacola as city engineer, then city manager.  Saw service with the Corps of Engineers in the Army during World War II, discharged with the rank of Captain.  Oliver Jr. married Kate Greenwood.  They were the parents of  two daughters and two son.  Oliver John Semmes Jr. died April 11, 1975, buried next to his wife Kate Greenwood Semmes in the O.J. Semmes family plot.