J. Roderick MacArthur, 63, a feisty, innovative philanthropist and businessman adept at making money, headlines and enemies, died of pancreatic cancer here today.

In the final weeks before his death, Mr. MacArthur had abandoned the legal fight he launched last year against fellow directors of the $1 billion charitable foundation set up by his late father, John D. MacArthur, an eccentric insurance and real estate tycoon.

J. Roderick MacArthur had accused the directors, a number of whom were longtime business associates of his father, of poor administration and excessive fee-taking.

Although the battle attracted substantial media attention, Mr. MacArthur's special significance on the contemporary American cultural scene rests firmly on pioneering the unique MacArthur Fellowship program, which makes unsolicited, no-strings-attached awards of $24,000 to $60,000 a year for five years to talented artists, scientists and others.

The annual selections draw worldwide attention. Mr. MacArthur, a self-made millionaire who built his own fortune with little help from his father, advocated the fellowships as a way to reward genius, and provide recipients with a period of time free from financial worries in which they can concentrate their creative energies.

"It's all very well to starve in a garret," Mr. MacArthur said in an interview several months ago. "But some areas of endeavor can't be handled that way. I don't think that keeping people poverty-stricken is going to help their creative juices . . . . Most people spend a hell of a lot of time worrying where their next buck is coming from . . . . "

The statement was vintage Rod MacArthur: pithy, blunt, realistic. And totally in character for an off-spring of the famous feuding MacArthur clan of writers and businessmen whose internecine spats have enlivened the U.S. scene for much of this century.

Among the better-known members of this family were Mr. MacArthur's uncle, Charles MacArthur, coauthor of "The Front Page," the classic comedy-drama about Chicago newspapering in the Roaring Twenties, and Mr. MacArthur's father, John D.

Mr. MacArthur was born Dec. 21, 1920, in San Francisco, attended Rollins College in Florida, and traveled in Mexico in the early 1940s, where he worked as a stringer, or occasional reporter, for the Associated Press. During World War II, he joined the civilian ambulance corps of the American Field Service, serving with the French Army. He participated in the 1944 Allied invasion of France and later served with a French underground resistance unit.

Returning to the U.S. several years after the war, Mr. MacArthur began working for his father, who was amassing a vast fortune running companies that specialized in selling low-cost, but immensely lucrative, life and health insurance policies. Within a few years, Mr. MacArthur had made several important innovations in the field.

Abrasive relations between father and son led Mr. MacArthur to strike out on his own. He had taken an interest in a company that engaged in sales of commemmorative collectors' porcelains. Realizing that the worldwide trade in these decorative plates was disorganized, Mr. MacArthur in 1973 founded the Bradford Exchange, which now brokers virtually every purchase or sale by plate collectors around the world.

The Bradford Exchange made Mr. MacArthur a multimillionaire in his own right, but not without difficulties from his father. In 1975, John D. MacArthur claimed the business as his own, seized the Bradford Exchange's valuable customer lists, and put its collection of 250,000 plates under lock and key.

Mr. MacArthur was up to this test. He struck back, organizing a private posse that raided his father's corporate headquarters in a Chicago suburb, hustling the cartons of plates into a fleet of waiting trucks and returning them to Mr. MacArthur's control. Father and son later made up their differences, and Mr. MacArthur was named in his father's will as a director of the John D. and Catherine T. MacArthur Foundation. With assets approaching $1 billion, it is one of the world's largest philanthropic institutions today, annually making charitable grants of nearly $100 million for health care, the arts, education, and other areas.

Mr. MacArthur helped shape those grant policies, and with the profits from his Bradford Exchange, founded his own foundation, which is named for him. In the philanthropic world, it is known as the "Little Mac," as distinguished from the foundation set up by his late father, which is called the "Big Mac."

Mr. MacArthur is survived by his wife, the former Christiane L'Entendart; two sons, a daughter, and a sister.