A World War II veteran, Bellmon served a single term in the Oklahoma House of Representatives, before running for governor.

In 1962, beating the studied journalist and well known constructor Bill Atkinson with 392,316 votes (55.3%), Bellmon became Oklahoma's first Republican governor since statehood in 1907.

[4] In 1968, he was serving as the national chairman for Richard Nixon's presidential election campaign, but then decided to run for the U.S. Senate, and won, unseating U.S.

Both candidates made their cases on the floor and nine Democrats voted along with all the Republicans to end the challenge and seat Bellmon.

During his service in the Senate, he sometimes took moderate positions that put him at odds with the largely conservative Oklahoma Republican Party: he supported Gerald Ford over Ronald Reagan in the 1976 presidential election (even though the state delegation was committed to Reagan);[5] he opposed a constitutional amendment to prohibit forced busing for the purpose of racially desegregating public schools; and he supported the Panama Canal treaty.

Bellmon was appointed the interim director of the Oklahoma Department of Human Services by Governor George Nigh, a Democrat, in 1982.

[5] As the tenures of Bellmon and his party colleague Bartlett had been followed by four terms of Democratic rule, Oklahoma Republican leaders asked him in 1986, if he would consider running for governor again.

Bellmon agreed to run, and he narrowly won the election in November with 431,762 votes (47.5%) over David Walters (405,295; 44.5%).

During his second term, Bellmon worked with Democrats in the Oklahoma legislature to pass an educational reform package, House Bill 1017, over the opposition of most Republicans.

Bellmon is notable for overseeing as governor both Oklahoma's final pre-Furman execution, when James French was electrocuted in 1966, and its first post-Furman, when Charles Coleman was put to death by lethal injection in 1990.

Bellmon died September 29, 2009, in Enid, Oklahoma, at the age of 88 after a long battle with Parkinson's disease.