[1][2] Harrison resigned as attorney general in April 1961 to run for governor, winning election that November with 63.84% of the vote, defeating Republican H. Clyde Pearson.

He helped to modernize state banking laws to attract investment and accelerated highway construction.

Part of Massive Resistance involved the closing of public schools in various Virginia cities and counties to prevent racially integrated classrooms.

After opinions by the Virginia Supreme Court on January 19, 1959, as well as a three-judge federal panel overturned much of the new Virginia legislation, Governor J. Lindsay Almond (previously attorney general) and Harrison decided not to defy those courts and allowed schools in Arlington and Norfolk to reopen.

[2] Another aspect of Massive Resistance involved new laws regulating attorney ethics, designed to attack practices of the NAACP, which was pursuing the desegregation actions.

Initially, the U.S. Supreme Court deferred to an upcoming decision of the Virginia Supreme Court about those new ethics rules in Harrison v. NAACP (1959), but the case came before it twice more in NAACP v. Button (1963) (which was reargued after Harrison resigned as attorney general to run for governor, and which Virginia lost under attorney general Robert Young Button.