Jenkins was admitted to the New York Bar in December 1923 and the PennsylvaniaBar in January 1924 and commenced practice in Wilkes-Barre, Pennsylvania. He served as assistant district attorney of Luzerne County from 1938 to 1946.
In April 1917, Jenkins enlisted as a private in the United States Army and was discharged as a first lieutenant on January 2, 1919. He enlisted in the Pennsylvania National Guard as a private in January 1926 and rose through the ranks to lieutenant colonel prior to induction into Federal service on February 17, 1941. He served four and a half years during the Second World War, during which time he was promoted to colonel, and was placed on inactive status on October 5, 1945. He was promoted to brigadier general (retired) in the Pennsylvania National Guard.
Jenkins was elected as a Republican to the Eightieth Congress (January 3, 1947–January 3, 1949) and was not a candidate for reelection in 1948 to the Eighty-first Congress. He once again served as the assistant district attorney of Luzerne County in 1949, and again in 1950. Thereafter he resumed his private law practice in Wilkes-Barre, where he died, aged 81. He was interred in Evergreen Cemetery in Shavertown, Pennsylvania.