[a] Barnes practiced law in a private practice (Gavin & Barnes) in Tulsa, Oklahoma from 1939 to 1941, when he became general counsel for the Tulsa plant of Douglas Aircraft Co. from 1941 to 1946.
Barnes worked on formulating legislation as assistant attorney for the Oklahoma Tax Commission from 1935 to 1939.
[2][3] Barnes resigned from the SBA in November, 1959, and soon joined Shearson, Hammill & Co., a national brokerage and underwriting firm, as a special consultant and later as a general partner.
In 1964, he joined the Western Wood Products Association in Portland, Oregon as Executive Vice President.
After that, he worked as an executive recruiter, a San Francisco real estate developer, and as a director for several corporations.