John Sherman Cooper was born in Somerset, Kentucky, on 23rd August, 1901. After graduating from Yale College in attended Harvard Law School. He was admitted to bar in 1928 and worked as a lawyer in Somerset, Kentucky.
A member of the Republican Party, Cooper was elected to the House of Representatives in Kentucky in 1928 and served as judge of Pulaski County (1930-38).
Cooper lived in Washington where he associated with a group of journalists, politicians and government officials that became known as the Georgetown Set. This included Frank Wisner, George Kennan, Dean Acheson, Richard Bissell, Desmond FitzGerald, Joseph Alsop, Stewart Alsop, Tracy Barnes, Thomas Braden, Philip Graham, David Bruce, Clark Clifford, Walt Rostow, Eugene Rostow, Chip Bohlen, Cord Meyer, James Angleton, William Averill Harriman, John McCloy, Felix Frankfurter, James Reston, Allen W. Dulles and Paul Nitze.
Most men brought their wives to these gatherings. Members of what was later called the Georgetown Ladies' Social Club included Katharine Graham, Mary Pinchot Meyer, Sally Reston, Polly Wisner, Joan Braden, Lorraine Cooper, Evangeline Bruce, Avis Bohlen, Janet Barnes, Tish Alsop, Cynthia Helms, Marietta FitzGerald, Phyllis Nitze and Annie Bissell.
After losing his seat in 1949 he returned to his legal practice. Later that year he was appointed delegate to the General Assembly of the United Nations and in as adviser to the Council of Ministers of the North Atlantic Treaty Organization in 1950.
In 1952 Cooper was again elected to the Senate. A strong opponent of McCarthyism Copper was one of the first senators to attack the tactics of Joseph McCarthy. After losing his seat he was appointed Ambassador to India (1955-56). Cooper was elected to the Senate for the third time in 1956.
After the death of John F. Kennedy, his deputy, Lyndon B. Johnson, was appointed president. He immediately set up a commission to "ascertain, evaluate and report upon the facts relating to the assassination of the late President John F. Kennedy." The seven man commission was headed by Chief Justice Earl Warren and included John Sherman Cooper, Gerald Ford, Allen W. Dulles, John J. McCloy, Richard B. Russell and Thomas H. Boggs.
The Warren Commission was published in October, 1964. It reached the following conclusions: "(1) The shots which killed President Kennedy and wounded Governor Connally were fired from the sixth floor window at the southeast corner of the Texas School Book Depository. (2) The weight of the evidence indicates that there were three shots fired. (3) Although it is not necessary to any essential findings of the Commission to determine just which shot hit Governor Connally, there is very persuasive evidence from the experts to indicate that the same bullet which pierced the President's throat also caused Governor Connally's wounds.... (4) The shots which killed President Kennedy and wounded Governor Connally were fired by Lee Harvey Oswald. (5) Oswald killed Dallas Police Patrolman J. D. Tippit approximately 45 minutes after the assassination. (6) Within 80 minutes of the assassination and 35 minutes of the Tippit killing Oswald resisted arrest at the theater by attempting to shoot another Dallas police officer. (7) The Commission has found no evidence that either Lee Harvey Oswald or Jack Ruby was part of any conspiracy, domestic or foreign, to assassinate President Kennedy. (8) In its entire investigation the Commission has found no evidence of conspiracy, subversion, or disloyalty to the U.S. Government by any Federal, State, or local official. (9) On the basis of the evidence before the Commission it concludes that, Oswald acted alone."
According to Gerald D. McKnight, the author of Breach of Trust: How the Warren Commission Failed the Nation and Why (2000): "Although Russell had support from Cooper and Boggs, he was the only one who actively dug in his heels against Rankin and the staff's contention that Kennedy and Connally had been hit by the same nonfatal bullet. Because of Russell's chronic Commission absenteeism he never fully comprehended that the final report's no-conspiracy conclusion was inextricably tied to the validity of what would later be referred to as the single-bullet theory."
The journalist, C. David Heymann, has argued: "Of JFK's many friends and admirers none was more anguished by his death than John Sherman Cooper. The Kentucky senator subsequently served on both the Warren Commission and on the committee selected by Jacqueline and Robert Kennedy to select a site and raise funds for the John F. Kennedy Library. Regarding his service on the Warren Commission, Senator Cooper publicly expressed dissatisfaction with the commission's findings, terming the group's 1964 report 'premature and inconclusive.' In no uncertain terms he informed Jack's surviving brothers, Robert and Teddy, that, having personally examined thousands of shreds of documentation, he felt strongly that Lee Harvey Oswald had not acted alone." Heymann claims that when Cooper expressed these thoughts to Jackie Kennedy, she responded: "What difference does it make? Knowing who killed him won't bring Jack back." Cooper replied: "No, it won't... But it's important for this nation that we bring the true murderers to justice."
Cooper was a critic of U.S. involvement in Vietnam. In 1969, he joined with Senator Frank Church to sponsor an amendment prohibiting the use of ground troops in Laos and Thailand. The two men also joined forces in 1970 to limit the power of the president during a war.
After leaving Senate in 1973, Cooper was appointed Ambassador to the German Democratic Republic (1974-76).
John Sherman Cooper died in Washington on 21st February, 1991.