Cook was born in Atlanta to James Leslie Cook and Bess Mims Cook. His father owned a number of men's clothing stores around the southeastern United States. Cook's mother, a member of the Mims family, have influenced the history of Georgia for over 200 years. Her grandfather's farm, called Red Oak, was destroyed by the invading army of General William T. Sherman during the Siege of Atlanta and the March to the Sea. The record of damages paid to this family by the Federal Government are in the archives of the Library of Congress and include the family's efforts to bring about a peaceful conclusion to the Civil War.

Cook attended Washington and Lee University and graduated valedictorian and summa cum laude with a Bachelor of Arts degree in 1947. His college education was interrupted by World War II, during which Cook was a lieutenant in the United States Navy in the Pacific Theater. He served on the USS DuPage which was hit by a kamikaze pilot during the war, but he was uninjured.^[1][2]

Upon leaving the military, Cook returned to Georgia and later, with Robert Mathis built the Peachtree Planning Corporation, an insurance company. He entered into the political arena in 1962 by serving as a member of the Atlanta Board of Aldermen, where he chaired the Planning and Development Committee and was a member of the Parks and Zoning Committees until 1970.^[2]

Cook was elected to the Georgia House of Representatives in 1965, and took office during the 1966 term.^[3] He was the first Republican elected county-wide in Fulton County to the Georgia House of Representatives. He remained in the legislature until 1972, serving as chairman of the Joint Senate–House Committee on Computerized Criminal Records and as a member of the Appropriations, Ways and Means, and Industry Committees.^[2][4] Cook unsuccessfully ran for Mayor of Atlanta in 1969, where he was defeated by Sam Massell. He returned to the House of Representatives and became chairman of the Georgia Republican Party and later ran unsuccessfully for Governor of Georgia in 1978 on the Republican ticket against Democratic incumbent George Busbee. His leading the ticket created a Republican majority in the Georgia Delegation to the United States Congress for the first time since Reconstruction.^[2]

In 1962, Cook made a speech in the Georgia State Capitol to take down the "Peyton Wall," a barrier that was built to stop black citizens from moving into a white section of Atlanta. His speech (Video part 1 on YouTube, Video part 2 on YouTube) incited the KKK to burn a cross on the lawn of his home in Buckhead. He encouraged Atlanta citizens to participate in urban renewal and contested systems that discriminated against minorities, particularly in regard to housing rules.^[1]

He was one of just five white representatives (out of 205) who voted to seat the duly elected African American candidate Julian Bond in the state legislature in 1966. The legislature removed Bond due to his anti-war positions. The United States Supreme Court returned him to office.^[1]

Cook was the lieutenant of Mayor's William B. Hartsfield and Ivan Allen, shepherding federal and state funding to the City of Atlanta resulting in unprecedented growth during the 1960s and 1970s. He counted Martin Luther King Sr., known as Daddy King, as a friend, and was instrumental, along with Mayor Allen and Coca-Cola CEO Robert Woodruff, in keeping Atlanta peaceful in the aftermath of the assassination of Dr Martin Luther King Jr. His career was championed by the Atlanta business community, particularly Mills B. Lane, Savannah native and CEO of the Citizens and Southern National Bank, (now Bank of America), and also James D. Robinson Jr., CEO of the First National Bank of Atlanta, (now Wells Fargo). Cook championed the careers of Paul Coverdell and Newt Gingrich, later a United States senator and Speaker of the House of Representatives respectively. Both men were trusted advisors to Cook and Speaker Gingrich noted this in a speech he made on C-Span decades later. (view video here^{[permanent dead link]})

The papers of Cook are housed at the Richard B. Russell Library for Political Research and Studies, University of Georgia Libraries.

Cook first married Bettijo Hogan Cook, a member of the Sewell family. The Sewells arrived in America at Jamestown, Virginia in 1610 and later settled downriver at Sewell's Point, currently a United States Navy base. Mr. Cook was married to Sidney Adamson, of the Philadelphia Adamson's, from the 1970s until her death on 23 January 2002. In 2003 he married Lane Young of Savannah and Atlanta at Blenheim Palace.

Cook was the father of two daughters and a son. His son, Rodney Mims Cook Jr., is President of the National Monuments Foundation, owner of the Millennium Gate at Atlantic Station in Atlanta and is currently coordinating the design for the memorial to John Adams and John Quincy Adams in Washington.^[5]

Cook died at his home in Atlanta on January 13, 2013, due to complications from heart failure. His funeral service was scheduled for January 19 at the Millennium Gate and Museum at Atlantic Station, to be followed by entombment in the Mims family vault at the Westview Abbey Mausoleum.^[6][7]

Cook was honored on Tuesday, January 15, 2013 in the Georgia House of Representatives Chamber Morning Order. The Honorable Joe Wilkinson delivered the eulogy on YouTube. On Wednesday January 17, Cook lay in repose at the Gothic City Hall Chamber. He was the only person to have this honor since Mayor Maynard Jackson. Visitation was at home in the Alexandra Park Chapel where Cook's flag-draped coffin had an Honor Guard of U.S. Navy, Atlanta Fire Department and Atlanta Police Department officers.

On Saturday, January 19, 2013, Cook's funeral ceremony was held at the Millennium Gate. Hundreds attended the ceremony led by the Very Reverend Sam Candler, Dean of the Cathedral of St. Philip. Civil Rights leader Ambassador Andrew Young delivered the eulogy. St. Philip's Cathedral choir and the Higher Ground Empowerment Gospel Choir performed. Mayor Kasim Reed, Fire Chief Kelvin Cochran, and Police Chief George Turner sent a fire and police department Honor Guard to complement the full Military Honor Guard. Several fire engines and police cars were part of the funeral motorcade to Westview Abby Mausoleum where Cook was laid to rest in the Mims Family vault.

Rodney Cook Sr. Park, a new park in the Vine City neighborhood, was named after the public figure.^[8][9][10] Atlanta's Downtown Connector, where Interstates 75 and 85 join between Midtown and Hartsfield-Jackson International Airport, was named for Cook in 2014. The symbolic meanings for this honor were Cook's efforts as head of the Highway Commission to build the road, as well as his Civil Rights efforts to bring all Atlanta citizens together and keep Atlanta race relations peaceful.

Georgia's 5th congressional district:^[11]

• Gary M. Pomerantz, Where Peachtree Meets Sweet Auburn, Rodney Cook 383, 389, 390, 391
• Atlanta Rising by Frederick Allen, Rodney Cook 163, 164, 165, 166; Atlanta Mayors' Race
• Atlanta and Environs by Garrett
• Notes on the 60s by Ivan Allen Jr.