[3] Davis began his career as a member of the U.S. Army Judge Advocate General's Corps where he served as trial counsel in the Republic of Korea and as government appellate counsel in Washington D.C. from 1964 to 1967.
In 1967 he returned to Kansas to engage in private practice in Leavenworth which he continued until 1984.
In 1993, Governor Joan Finney promoted him to the Kansas Supreme Court.
In January 2009 he became chief justice when Kay McFarland resigned due to state mandated age limits.
He was a member of the Governor's Advisory Commission on Alcoholism from 1971–1976 under Governor Robert Docking, chairman of the board of trustees for St. John's Hospital in Leavenworth from 1980 to 1984, director and president of Leavenworth County Community Corrections Board in 1980–1984, director of the Leavenworth Historical Society from 1970 to 1975, general counsel and board of directors for Leavenworth National Bank and Trust Co. from 1972 to 1984, and a council member for St. Mary's College in 1984.