Boner was born in East Nashville, traditionally a politically active part of the city. A star at East Nashville High School, from which he graduated in 1963, he subsequently entered the fields of teaching and coaching, and for two years was basketball coach at Trevecca Nazarene College. He graduated from Middle Tennessee State University in 1967, and received a master's degree from the former Peabody College in 1969. He also became a popular and respected high school and middle school sports referee. In 1970, he was elected to the Tennessee House of Representatives, a part-time position, for the first time, serving until 1972. Leaving the field of education, he became a bank official at First American National Bank and enrolled in the former YMCA Night Law School, a school specializing in part-time, mid-career students. He later graduated from this institution, but never took the bar exam to be admitted to the practice of law. While employed at the bank, Boner was again elected to the State House in 1974. He moved to the Tennessee State Senate in 1974. After only one term he then made the decision to enter the Democratic primary against incumbent 5th District Congressman Clifford Allen in 1978.
Congress
Several other persons had also decided to challenge Allen, a long-time Nashville political figure who appeared to be in declining health and who seemed vulnerable. Shortly before the deadline for candidates to withdraw from the race, Allen suffered a massive stroke. All of Allen's opponents except Boner withdrew from the race, apparently out of concern for "kicking a man when he's down." When Allen died on the day after the withdrawal deadline, Boner was virtually unopposed for the nomination, facing only a write-in campaign that went nowhere. This was tantamount to victory in November, as the Republicans had lost interest in a district they hadn't won since 1874. He was reelected four times with no substantive opposition. Boner's tenure in Congress was largely uneventful. He established a reputation for a staff devoted to excellent constituent service, and otherwise as a moderate Southern Democrat backbencher, whose largest legislative accomplishment was a bill recognizing "National Sewing Month", something which subsequent opponents would later point to with glee. In 1986, he came under investigation by the House Ethics Committee for his close relationship with a government contractor.
Mayor
In 1987, Nashville Mayor Richard Fulton was prevented from running for a fourth term. Boner quickly jumped into the race, seeing an opportunity to come home, and also to end the investigation. He was opposed by a large field, notably managed health care executive Phil Bredesen. Boner won the first round, but came up short of a majority. Under the Metro Charter, Boner faced runner-up Bredesen in a runoff. Boner won, largely by emphasizing that he was a Nashville native and Bredesen was a Northerner. He was the last native-born Tennessean to serve as Nashville mayor until David Briley became mayor in 2018.
Appearance on ''The Phil Donahue Show''
During his term as mayor, Boner made a controversial appearance on the October 15, 1990 episode of The Phil Donahue Show. Boner appeared on the show with Traci Peel, a country singer in Nashville. The couple were engaged, making their romance controversial, as Boner was still married to his third wife. It was reported that Peel had previously told a Nashville reporter that the Mayor's passion could last for seven hours. At one point in the Donahue appearance, Boner played harmonica, while Peel sang "Rocky Top". Boner and Peel would eventually marry and then divorce after Peel caught Boner cheating two years into the marriage.
After term as mayor
Boner opted not to seek reelection for a second term—to date, the only mayor not to do so since the creation of the Metro government. Following retirement from political office, Boner briefly became a businessman, owning a pallet factory in Tompkinsville, Kentucky, and then becoming a restaurant franchisee in Atlanta. Boner eventually returned to the Nashville area, becoming a social studies teacher at Franklin High School in Franklin, Tennessee. Sources had said that Boner had become a driver's ed instructor for the Williamson School System, and was "honest and open about the fact that he screwed up in office." In 1995 and 1996, Boner hosted a nightly hour-long television interview show on Nashville's WNAB called Prime Talk. Boner is reportedly retired and living with his wife, Kay, in Franklin, Tennessee.
