Before reaching the majors, he attended David Starr Jordan High School and then a catcher at Pepperdine University, where he was named an All-American in 1963.

In 1977, Gail played for the Nankai Hawks of the Pacific League, before retiring from professional baseball to pursue a full-time career in medicine.

In Nolan Ryan's first career no-hitter (May 15, 1973), Hopkins appeared as a pinch-hitter in the bottom of the 8th inning, and hit a bloop fly that Angels shortstop Rudy Meoli caught with a running catch.

After his baseball career ended, he earned four graduate degrees: a Master's in Religion at Pepperdine, a Master of Divinity from United Theological Seminary, a Doctorate in Biology at the Illinois Institute of Technology and an M. D. degree from Rush Medical College where he was a member of Alpha Omega Alpha Honor Medical Society.

He later served as the Chairman of the Board of Trustees for the Ohio Valley University, a Churches of Christ affiliated college in West Virginia.