English's first job in politics was as a staff member for the majority caucus of the California State Assembly. Later, he worked as a legislative staffer in the U.S. House of Representatives. After serving as the executive director of the Oklahoma Democratic Party, English was elected as a Democrat to Congress representing Oklahoma's 6th Congressional District. English was re-elected to Congress nine times. He was one of the most conservative Democrats in the chamber, which was not surprising given the nature of his district. It spanned from the Oklahoma Panhandle to northeastern Oklahoma City, including along the way some of the most rural and conservative territory in Oklahoma. While in Congress, English served on the Committee on Agriculture and the Committee on Government Operations. He also was the Chairman of the Select Committee on Narcotics Abuse and Control. In addition, English chaired the Government Information, Justice and Agriculture Subcommittee where he won approval for the military to use aircraft and radar to assist Custom agents in the interdiction of drug smugglers. During the 1985–86 term, English was instrumental in securing a $20 million federal hub in Oklahoma City to assist in the war on drugs which is currently located at the Will Rogers Airport. In 1993, Glenn was also effective in halting a plan to reduce the work of the Rural Electrification Administration. In a series of meetings between the Committee on Agriculture and the White House, Glenn successfully interceded between the two organizations to enhance REA's status and the quality of life for rural America. English resigned from the House on January 7, 1994, and was succeeded in Congress by Frank Lucas, a Republican.
Upon his departure from Congress in 1994, English became CEO of the National Rural Electric Cooperative Association, based in Arlington, Va. NRECA is the national trade association for the Nation's 900-plus locally owned, consumer-controlled, non-profit electric cooperatives which currently delivers electricity to 42 million Americans in 47 states. On May 5, 2010, after serving as chief executive officer for NRECA for 16 years, English was inducted into the Cooperative Hall of Fame at the National Press Club in Washington, DC.
