McWherter was born in Palmersville, in Tennessee's northwest corner. A member of the United Methodist Church, McWherter served for 21 years in the Tennessee National Guard before retiring with the rank of captain.
He began his political career in 1968 when he won a seat in the Tennessee House of Representatives from Weakley County. After only serving two terms in the General Assembly, he was elected Speaker of the House. He held this position for 14 years, longer than anyone in Tennessee history at that time. During his time in the legislature, he served in the following areas: State Building Commission Joint Fiscal Review Committee, the Council on Pensions and Retirement, the Tennessee Agricultural and Industrial Development Commission and the State Agri-Industries Board. He was also the chairman of the House Calendar and Rules Committee, the House Finance, Ways, and Means Committee and the House General Welfare Committee.
In 1986, he won a spirited primary over Public Service Commissioner Jane Eskind and Nashville mayor Richard Fulton for the Democratic nomination for governor. He faced former Republican governor Winfield Dunn in what was initially considered one of the hotter races of the 1986 cycle. However, Dunn's campaign stalled when 1st District Congressman Jimmy Quillen, the de facto leader of the Republican Party in East Tennessee, refused to support Dunn and encouraged several prominent East Tennessee Republicans to withhold their support as well. Quillen had never forgiven Dunn for his opposition to a medical school at East Tennessee State University. Without significant support in East Tennessee for Dunn, McWherter was virtually assured of election in November. Dunn was able only to hold McWherter's victory margin to just under nine points due to strong support from his former base in Memphis. While several former state House speakers have risen to the governorship, McWherter is the only person to hold that post right up to the time he was elected governor.
During his first term, McWherter insisted that all formal governmental proceedings be open to the public and press, thus implementing the spirit, as well as the letter, of the "sunshine law" he had helped to author and sponsor while a member of the House. He had opened doors to minority groups in Tennessee as Speaker by appointing the first black committee chairmen in Southern history and assisted women into influential leadership roles in the legislature. His "21st Century Schools" education reform program launched similar programs in other states and his replacement of the Medicaid program with the TennCare system gained national attention. As governor, he also served nationally and local on councils and committees including the board of governors, Council of State Governments, the Executive Committees of the Southern Conference, the Weakley County Head Start Program and the Executive Committee of the Northwest Tennessee Economic Development District.
In 1990, McWherter was invited to speak at a chapel service at Freed-Hardeman University in Henderson, TN at the request of his life-long friend, E. Claude Gardner, then President of the University. Due to McWherter's connection with the beer industry and the conservative nature of the school, this created an outcry among faculty and staff who boycotted the chapel service. Not long after this event, Gardner was terminated by the University's Board of Directors and replaced with Dr. Milton Sewell who remains as the university's president.
He was overwhelmingly re-elected to a second term in 1990, carrying approximately two-thirds of the vote over the essentially token candidacy of the Republican nominee, first-term state representative Dwight Henry. (Many prominent Tennessee Republicans actually supported McWherter for re-election, some tacitly, others fairly openly.) A tax study commission appointed during his first term reported at the beginning of his second, recommending a state income tax be implemented. An income tax has long been considered the third rail of Tennessee politics. McWherter gave the idea lukewarm support at first, but the idea was eventually dropped entirely, not to resurface again during his time as governor.
During McWherter's second term, Senator Al Gore was elected Vice President, thus creating a vacancy in the Senate. McWherter appointed his deputy governor, Harlan Matthews, to serve as U.S. Senator until the 1994 election.
McWherter would have been an overwhelming favorite for a third term if he had been permitted to run for one by the state constitution; when asked about this, he stated that he would not have run for another term even if it had been permissible. Following the end of his second term as governor in 1995, McWherter was appointed to the Board of Governors of the United States Postal Service by President Bill Clinton. McWherter still lives in Tennessee, where he is still very active in the Tennessee Democratic Party. He owns several nursing homes and a beer distributorship.
McWherter was married to the late Bette Jean Beck McWherter and is the father of two children. His son Michael Ray McWherter is a businessman in Dresden, Tennessee, and his daughter Linda Ramsey is a doctor of physical education at the University of Tennessee at Martin.