A native of Paris, Tennessee, Buchanan served in the United States Navy from 1945 to 1946 and then relocated to Alabama to attend Samford University in Birmingham.

"[4] Buchanan led the three-candidate field in 1962 with 141,202 votes but failed to dislodge the eighth-place Democratic candidate, Representative Carl Elliott of Jasper.

In 1964, he was handily elected to Congress from the Birmingham-based 6th district, having unseated the 10-year incumbent Democrat, George Huddleston Jr., by a staggering 21-point margin.

Partly as a result, Barry Goldwater easily carried the district en route to winning 69 percent of Alabama's popular vote.

In an interview with the Washington Post in 1976, Buchanan explained his change on social views: "When you’re deeply involved in a biracial entity, you think of people as brothers and sisters."

For fourteen years, he was a member of the Foreign Affairs Committee, where he championed the rights of people behind the Iron Curtain, especially Jewish and Christian dissidents, as well as the black majorities in Southern Rhodesia and South Africa.

Buchanan, alongside fellow centrist Republicans Alphonzo E. Bell Jr. and John B. Anderson, also supported the creation of a Martin Luther King, Jr. statue in the Capitol.

Auburn University historian Wayne Flynt described Buchanan as a "centrist in an age where centrism was beginning to be challenged and would finally result in the polarization of American politics into left and right."

[11] In that capacity, he traveled extensively, participating in frequent debates with leaders of the Religious Right on radio, television, and various platforms throughout the United States.

Appearances in the media included McNeil-Lehrer NewsHour, Crossfire, Larry King Live, Charlie Rose, and other news programs.

[13] Al Quie, Republican representative and governor of Minnesota, who served with Buchanan, said of him: "There was a basic goodness, solidness, that didn't take long to recognize and respect.