The longtime professional quarterback, who went on to become a New York congressman, presidential candidate, Cabinet secretary and vice presidential candidate, died at his home in Bethesda, Md.
"He was a bleeding-heart conservative," said Edwin J. Feulner, a former campaign advisor and president of the Heritage Foundation who confirmed news of Kemp's death. "He was a good friend and a real hero to a lot of us."
Kemp first gained national prominence with the San Diego Chargers in the early 1960s and then went on to lead the Buffalo Bills to the American Football League championship in 1964 and 1965.
He used his popularity on the football field to win election from a Buffalo-area district to the U.S. House of Representatives, where he served from 1971 to 1989.
As a congressman, Kemp was one of the few members of the House -- along with Democratic Speaker Thomas P. "Tip" O'Neill -- to have national name recognition. With his Kennedyesque hairstyle, boyish good looks, unbounded enthusiasm and raspy voice, Kemp seemed a natural to bring new energy and interest to the Republican Party when he ran with Sen. Bob Dole of Kansas in 1996.
The congressman was the leading architect of the Kemp-Roth tax bill, first proposed in 1978 with Sen. William Roth of Delaware, that proposed a 30% cut in federal taxes over three years. Kemp's 1979 book, "American Renaissance: A Strategy for the 1980s," contained what became known as Reaganomics during Ronald Reagan's presidency and helped redefine the GOP's economic identity.
"Jack more than any other person made Reagan aware of the potential appeal of supply-side economics, but Reagan probably would have come to that conclusion on his own because that's where the Republicans were headed," said Reagan's biographer Lou Cannon.
Kemp, as much as anybody, helped convince Reagan to embrace supply-side economics, designed to stimulate growth through tax reduction.
Kemp's tax bill was defeated in the House, but a similar measure was approved two years later, offering a 25% cut in taxes. He favored a return to the gold standard and took a hard line against the Soviet Union, supported aid for the Nicaraguan Contras and was a firm friend of Israel.
In many ways Kemp was ahead of his time in Republican circles, calling for the party to embrace all races and ethnicities and pushing for inclusion of blacks, Latinos and Jews.
"He was viewed very much as not only the carrier of supply-side economics, going back to the Reagan days, but he was really the guy who always talked about the 'big tent,' " Feulner said Saturday.
Kemp always thought about how to "add and multiply" the party, Feulner said.
Viewing himself as a neo-conservative, Kemp forged a new conservative activism among younger Republicans, breaking with the moderate old guard of the party that included George H.W. Bush, Dole and House stalwarts like Robert Michel. In the process, he became an ideological model for a generation of leaders that included future House Speaker Newt Gingrich of Georgia and Majority Leader Trent Lott of Mississippi.
"Jack rose to be a major national political figure and somebody considered as a presidential candidate on the strength of his personality, his drive and ideas," Norman J. Ornstein, a resident scholar at the American Enterprise Institute, told The Times some years ago. "That's not something that happens very often for House members."
But despite his looks and charisma, he did poorly on the national stage. His economic concepts, which he sold on the stump with the zeal of a fundamentalist preacher, seemed wonkish and failed to convert voters. His campaign style was seen as undisciplined and impatient. Political analysts saw him as unwilling to play politics in a manner what would bring victory at the polls.
"If I could remove two-thirds of your knowledge and three-fourths of your vocabulary, I could make you into a decent candidate," veteran Republican consultant Edward J. Rollins recalled telling him.
Kemp was born in Los Angeles on July 13, 1935. He was the third of four sons of Paul R. Kemp, who owned a small trucking company in downtown Los Angeles, and Frances Pope Kemp, a social worker who spoke fluent Spanish. The Kemps were Republicans and Christian Scientists. (Kemp became a Presbyterian after his marriage and for years considered himself a born-again Christian).