In early 1941, he enlisted in the Army. As a soldier of the 77th Infantry Division, he fought in World War II, advancing from Private to Lieutenant Colonel. He earned a Bronze Star with Oak Leaf Clusters and a Purple Heart for his actions aboard the troopship USS Henrico, after a kamikaze attack during the invasion of Okinawa. His image appears in the Infantry Officer Hall of Fame at Fort Benning, Georgia.

On February 14, 1948, Winthrop married actress Jievute “Bobo” Paulekiute (September 6, 1916 – May 19, 2008). She was previously married to Boston Brahmin socialite John Sears Jr. The wedding took place in Florida, and at the reception, a choir sang Negro spirituals. On September 17, 1948, she gave birth to their son, Winthrop Paul “Win” Rockefeller.

The couple separated in 1950 and divorced in 1954. Bobo got custody of Win.

Rockefeller moved to central Arkansas in 1953 and established Winrock Enterprises and Winrock Farms atop Petit Jean Mountain near Morrilton in Conway County.

In 1954, Republican Pratt C. Remmel polled 37 percent of the vote in the gubernatorial general election against Democrat Orval Faubus. It was a good showing for a Republican candidate in Arkansas, compared to previous races in the 1940s and early 1950s. Twelve years later, Rockefeller would build upon Remmel’s race and win the governorship for the Republican Party.

In 1955, Faubus appointed Rockefeller chairman of the Arkansas Industrial Development Commission (AIDC).

On June 11, 1956, Rockefeller wed the Seattle-born socialite Jeanette Edris (1918–1997). She had two children, Bruce and Ann Bartley, from a previous marriage. Winthrop and Jeanette had no children together and divorced shortly after he left the governorship in 1971.

In 1960, Rockefeller did not seek the governorship but instead raised funds for the Republican nominee, Henry M. Britt, a conservative lawyer from Hot Springs, the seat of Garland County. Britt lost in every county and barely polled 30 percent of the statewide vote in his loss to Faubus. In 1961, Rockefeller was named Arkansas Republican national committeeman, having succeeded Wallace Townsend, a lawyer in Little Rock who had held the position since 1928. In 1962, Rockefeller supported Willis Ricketts, another in a long line of failed Republican candidates who sought to topple Faubus. He also supported a slate of Republican legislative candidates. Soon, he quarreled with state Republican party chairman William L. Spicer of Fort Smith over the direction of the party. Spicer favored a stronger conservative approach compared to Rockefeller’s moderate-to-liberal outlook.

Rockefeller resigned his position with the AIDC and conducted his first campaign for governor in 1964 against Faubus. His campaign was ultimately unsuccessful, but Rockefeller energized and reformed the tiny Republican Party to set the stage for the future. In 1964, Osro Cobb, a Republican former state chairman who had also served as United States Attorney for the Eastern District of Arkansas, refused to endorse Rockefeller but openly endorsed Faubus, who subsequently gave Cobb a temporary appointment to the Arkansas Supreme Court.

The legacy of Winthrop Rockefeller lives on in the form of numerous charities, scholarships, and the activities of the Winthrop Rockefeller Foundation and the Winthrop Rockefeller Charitable Trust, including Winrock International, an international nonprofit organization based in Little Rock, Arkansas whose mission is to empower disadvantaged people, increase economic opportunity, and sustain natural resources. The Winthrop Rockefeller Foundation provides funding for projects across Arkansas to encourage economic development, education, and racial and social justice. In 1964, he founded Museum of Automobiles on Petit Jean Mountain, which after his death in 1973 was given to the Arkansas State Parks system; a non-profit organization was formed to run the museum; in March 2007, the Charitable Trust pledged $100,000 for its ongoing operations if the museum raised an equal amount by the end of that year.

1964 General Election for Governor Orval Faubus (D) (inc.) 57% Winthrop Rockefeller (R) 43%

When Rockefeller made his second run in the 1966 election, only 11 percent of Arkansans considered themselves Republicans. But Arkansans had tired of Faubus after six terms as governor and as head of the Democratic “machine”. Democrats themselves seemed to be more interested in the reforms that Rockefeller offered in his campaign than “winning another one for the party”. An odd coalition of Republicans and Democratic reform voters catapulted Rockefeller into the governor’s office, as he defeated a segregationist Democratic former Justice of the Arkansas Supreme Court, James D. Johnson of Conway in Faulkner County, who preferred the appellation “Justice Jim”.

Former state Republican chairman Osro Cobb reversed himself in 1966 and endorsed Rockefeller. He explains:

Other Rockefeller running-mates, such as former Democratic State Representative Jerry Thomasson of Arkadelphia, who sought the office of attorney general in 1966 and 1968, and Leona Troxell of Rose Bud in White County, who ran for state treasurer in 1968, were defeated.

Two Republicans ran for U.S. Representative on the Rockefeller ticket in 1966. John Paul Hammerschmidt, the outgoing party chairman, won in the northwestern Third District. Lynn Lowe, a Texarkana farmer, who later served as party chairman from 1974–1980, lost in the southern Fourth District race to the Democrat David Pryor.

1966 Republican Primary for Governor Winthrop Rockefeller 98% Gus McMillan 2%

1966 General Election for Governor Winthrop Rockefeller (R) 54% James D. “Justice Jim” Johnson (D) 46%

In 1967, Rockefeller named an FBI agent, Lynn A. Davis, to head the state police with orders to halt illegal gambling in Hot Springs. After sensational raids against the mobsters, Davis was forced out as police director 128 days later when the Arkansas Supreme Court ruled that he did not meet the strict 10-year residency requirement for the appointment. Democratic lawmakers refused to change the rule to allow Davis to serve. The Hot Springs raids were the No. 1 news story in Arkansas in 1967 as determined by the Associated Press.

At the 1968 Republican National Convention, Winthrop Rockefeller received backing from members of the Arkansas delegation as a “favorite son” presidential candidate. He received all of his state’s 18 votes; his brother Nelson, then concluding a major presidential bid against Richard M. Nixon, received 277. This was the only time in the 20th century that the names of two brothers were placed into nomination at the same time.

Urwin determined that Rockefeller’s negatives created public perceptions of “his personal flaws, rather than his accomplishments or lack of them, as governor.” Considered a weak administrator, he depended too heavily on staff, so improperly managed that the employees often failed to answer mail. He was habitually tardy to meetings. A special legislative session in May 1968 was particularly disastrous. An Oliver Quayle poll in 1968 declared that Rockefeller seemed “strange, alien, and foreign” to many voters. The poll maintained that many thought Rockefeller sought too much power, that he drank too much, and that he spent too little time in his office. A majority said that the wealthy Rockefeller, despite his interest in “good government,” could not understand the problems of common people on restricted incomes or those in the middle class with limited investment opportunities.

Rockefeller won re-election in November 1968, having defeated Marion H. Crank, a state legislator from Foreman in Little River County, who had won the Democratic nomination in a heated fight with Virginia Morris Johnson, wife of Jim Johnson and the first woman ever to seek the office of governor of Arkansas. Newly reelected, Rockefeller proposed tax increases to fund additional reforms and his second term began on January 14, 1969. Rockefeller and the legislature dueled with competing public-relations campaigns and Rockefeller’s plan ultimately collapsed in the face of public indifference.

1968 Republican Primary for Governor Winthrop Rockefeller (inc.) 95% Sidney K. Roberts 5%

1968 General Election for Governor Winthrop Rockefeller (R) (inc.) 52% Marion Crank (D) 48%

Much of Rockefeller’s second term was spent in conflict with the opposition legislature. In 1969, he told the lawmakers that his reelection the previous November had meant that a slim majority of voters had approved of tax increases. He proposed to spend half of the new revenues sought on education, 12 percent on health and welfare, 10 percent on local government, and the remainder on state employee salaries and streamlined services. “There are no frills in what I am proposing … . no luxuries … . no monuments to me as an individual … . I implore every member of the General Assembly as I have myself: Listen to the voice of the people … . not to the selfish interests.”

In 1970, it was disclosed that Rockefeller had maintained a list of militants for use by law enforcement to prevent potential disorders on Arkansas college and university campuses. The list drew opposition from some of his opponents, including an unsuccessful Democratic primary hopeful, state House Speaker Hayes McClerkin of Texarkana. McClerkin argued that the list may have contained the names of those who merely disagreed with Rockefeller politically.

In 1970, the Arkansas GOP under Rockefeller hired its first paid executive director, Neal Sox Johnson of Nashville in Howard County. Johnson left the position in 1973 to take a high position with the former Farmers Home Administration in Washington, D.C., and was replaced by Ken Coon, who carried the party’s gubernatorial banner in 1974 against David Pryor.

In the 1970 campaign, Rockefeller expected to face Orval Faubus, who led the old-guard Democrats, but the previously unknown Dale Bumpers of Charleston in Franklin County rose to the top of the Democratic heap by promising reforms. Bumpers’ charisma and “fresh face” were too much for an incumbent Republican to overcome. Rockefeller lost his third-term bid, but he had inadvertently propelled the Democrats to reform their own party. Maurice Britt managed the 1970 campaign, and he was replaced on the Republican ticket for lieutenant governor by Sterling R. Cockrill of Little Rock, the former Democratic House Speaker in Rockefeller’s first term. Cockrill switched parties in the spring of 1970 to make the race; he was defeated by the Democrat Bob C. Riley but finished 35,000 votes ahead of Rockefeller.

With the 1970 elections, the Republicans were reduced to a single member of each legislative chamber, Preston Bynum of Siloam Springs in the House and Jim Caldwell in the Senate. Danny Patrick, elected with Rockefeller in 1966 and 1968, went down to defeat in Madison and Carroll counties at the hands of Stephen A. Smith, who at twenty-one became Arkansas’ youngest-ever state legislator, a designation that Patrick himself had taken only four years earlier.

1970 Republican Primary for Governor Winthrop Rockefeller (inc.) 95% James K. “Uncle Mac” MacKrell 2% R.J. Hampton 2% Lester Gibbs 1%

1970 General Election for Governor Dale Bumpers (D) 62% Winthrop Rockefeller (R) (inc.) 32% Walter L. Carruth (AIP) 6%

Before he left office, Rockefeller appointed a young public administrator, Jerry Climer, to the vacant post of Pulaski County clerk. Two years later, Climer ran for secretary of state. He later founded two Washington, D.C.-based “think tanks.” and left office on January 12, 1971.

In 1972, Rockefeller persuaded Len E. Blaylock of Perry County, his former welfare commissioner known for expertise in government administration to be the Republican gubernatorial nominee. Blaylock lost to Bumpers by an even greater margin than had Rockefeller in 1970. Rockefeller that year also supported the unsuccessful candidacy of Wayne H. Babbitt, a North Little Rock veterinarian who became the only Republican ever to challenge the reelection of U.S. Senator John L. McClellan.

In September 1972, Rockefeller was diagnosed with inoperable pancreatic cancer and endured a devastating round of chemotherapy. When he returned to Arkansas the populace was shocked at his gaunt and haggard appearance.

Winthrop Rockefeller’s son and only child, Win, served as Arkansas lieutenant governor, having won a special election in 1996 to succeed Mike Huckabee. Winthrop Paul Rockefeller then won two full four-year terms in 1998 and 2002. Like his father, Win Paul Rockefeller’s political career was cut short by a devastating cancer.

As a dramatic last act, Governor Rockefeller, a longtime death penalty opponent, commuted the sentences of every prisoner on Arkansas’s Death Row and urged the governors of other states to do likewise. Thirty-three years later, in January 2003, Illinois’ lame duck governor, George Ryan, would do the same, granting blanket commutations to the 167 inmates then sentenced to death in the state.