J. C. Penney was born on September 16, 1875, on a farm outside of Hamilton, Caldwell County, Missouri. He was the seventh of twelve children, only six of whom lived to adulthood, born to James Cash Penney Sr. and Mary Frances (born Paxton) Penney. Penney’s father was a Baptist preacher and farmer whose strict discipline included making his son pay for his own clothing once he reached his late pre-teens.

In 1898, James Cash Penney began working for a small chain of stores in the western United States called the Golden Rule stores. In 1902, owners Guy Johnson and Thomas Callahan, impressed by his work ethic and salesmanship, offered him a one-third partnership in a new store he would open. Penney invested $2,000 and moved to Kemmerer, Wyoming, to open a store there. He participated in opening two more stores, and when Callahan and Johnson dissolved their partnership in 1907 he purchased full interest in all three stores.

Penney was married three times. His first marriage, to Bertha Alva Hess (1869–1910) in 1899, produced two sons before her death from pneumonia:

After Bertha’s death in 1910, he married Mary Hortense Kimball (d. 1923) in July 1919. Mary gave birth to their son before her death of unspecified medical issues:

Penney was a Freemason most of his adult life, being initiated into Wasatch Lodge No. 1 Free and Accepted Masons of Utah, on April 18, 1911. A member of both the Scottish and York Rites, Penney was coroneted a 33rd Degree on October 16, 1945, and received the Gold Distinguished Service Award by the General Grand Chapter, Royal Arch Masons, in Kansas City, Missouri, in 1958. He typically wore a large ring showing his Masonic degree.

By 1912, there were 34 stores in the Rocky Mountain States. In 1913, he moved the company to the Kearns Building in downtown Salt Lake City, Utah. The company was incorporated under the new name, J. C. Penney Company. In 1916, he began to expand the chain east of the Mississippi and during the 1920s, the Penney company expanded nationwide, with 120 stores in 1920 (mostly still in the west). By 1924, Penney reported income of more than $1 million annually. The number of stores reached 1,400 by 1929. The large income allowed him to be heavily involved in many philanthropic causes during the 1920s. By 1921 he had a home (Belle Isle) on Biscayne Bay in Miami. Penney and partner Ralph W. Gwinn had invested heavily in Florida real estate including 120,000 acres (490 km) in Clay County. Some of this land became Penney Farms. This was also the start of Foremost Dairy Products Inc. Penney later recruited Paul E. Reinhold to run the dairy. Most of this work was halted when the stock market crash of 1929 and the Clutch Plague left Penney in financial ruin.

In 1926, Penney married Caroline Marie Autenrieth (1895–1992). She was badly hurt in 1928 when she fell from a horse at their estate in White Plains. They had two daughters:

Even after relinquishing daily operating management of the company, Penney continued his active involvement in managing the company and its stores. In 1940, during a visit to a store in Des Moines, Iowa, he trained a young Sam Walton on how to wrap packages with a minimal amount of paper and ribbon. He remained chairman of the board until 1946, and after that, as honorary chairman until his death in 1971. Until the end of his life, he continued to go to his offices. Penney directed his stores to be closed on Sunday so employees could attend church.

In 1953 the Springfield (MO) Chamber of Commerce presented Penny with a “Ozark Hillbilly Medallion” and a certificate proclaiming him a “hillbilly of the Ozarks.”

Penney founded the James C. Penney Foundation in 1954. The foundation was restructured in 1999 as the Penney Family Fund, and is no longer affiliated with J. C. Penney Co., Inc., or its corporate giving program. Today, the fund is part of the Common Counsel Foundation, an Oakland, California, consortium of family philanthropic foundations and individual donors. The Penney Family Fund endows organizations in Oregon, California, and Washington state that work to advance human rights, community social, political, economic empowerment, government accountability, and environmental sustainability.

In 1960 Penney teamed up with the University of Missouri to establish the Penney-Missouri Awards to recognize excellence in Women’s Page journalism, hoping to improve the sections where his stores most often advertised.

Penney lived in New York City at 888 Park Avenue, though he spent the winters in Palm Springs, California. On December 26, 1970, Penney fell and fractured his hip. Just a few weeks later, he suffered a heart attack and never fully recovered. He died on February 12, 1971. The Reverend Dr. Norman Vincent Peale delivered the eulogy at the funeral. Penney was buried in Woodlawn Cemetery in the Bronx, New York City, not far from that of fellow retail entrepreneur, F. W. Woolworth. His estate was valued at approximately $35 million.