Following graduation, he joined the firm of Gibson, Ochsner, Harlann, Kiney, & Morris in Amarillo, Texas as an associate partner.
He was subsequently recruited by Dean W. Page Keeton of the University of Texas School of Law and joined the faculty in 1965.
From 1971-73 Professor Gibson took a leave of absence to serve as an attorney advisor to the Federal Power Commission.
Professor Gibson contributed to continuing legal education in Texas in a variety of ways.
He was one of the founders of the Mortgage Lending Institute (which was later named in his honor) and helped establish standards for continuing legal education in Texas.