H.F. “Gerry” Lenfest, who made a $1 billion fortune in the cable industry and gave almost all of it away, supporting schools, museums, journalism and the arts in Philadelphia and beyond, died Aug. 5 at a hospital in Philadelphia. He was 88.

The cause was complications from chronic illness, said Fred Stein, a family spokesman.

Mr. Lenfest and his wife, the former Marguerite Brooks, made about $1.2 billion when they sold Suburban Cable to Comcast in 2000. The Lenfests immediately set out to give away the fortune. By 2014, as Mr. Lenfest stepped in to help Philadelphia’s ailing newspapers, he estimated he had given away $1.1 billion.

“Money is a responsibility when you have that kind of wealth. I’ve tried to do right by it. Perhaps the greatest opportunity came with the ownership of these newspapers,” Mr. Lenfest said in 2016 when he donated the Philadelphia Inquirer and its sister publications to a newly created nonprofit. “What would this city be without the Inquirer and Daily News?”

The Lenfests also gave to the Philadelphia Museum of Art, Barnes Foundation, Kimmel Center for the Performing Arts and Mr. Lenfest’s alma maters: Mercersburg Academy in Pennsylvania, Washington and Lee University in Lexington, Va., and Columbia University.

Marguerite’s alma mater, Wilson College in Chambersburg, Pa., also received funds. Mr. Lenfest also gave $50 million to champion the new Museum of the American Revolution, which opened in April 2017 and, he felt, provided the “missing link” to tie together the city’s historic sites.

Their three children didn’t need the money — they were given stakes in Mr. Lenfest’s cable company when it wasn’t worth much — and Mr. Lenfest said he feared a permanent foundation would do more to perpetuate itself than help others.

Notable deaths in 2018 and 2019: Nipsey Hussle, George H.W. Bush, Stan Lee, John McCain, Aretha Franklin and other famous faces we’ve lost

Nipsey Hussle, a Grammy nominated rapper who sought to revive South Los Angeles, died at age 33 on March 31. Read the obituary (Matt Winkelmeyer/Getty Images for Warner Music)

“During your lifetime, you can direct how your wealth is spent for the most good. But after your death, it is problematic. You don’t have the control,” he told the Inquirer in 2004.

Within four years, the Lenfests had given away $325 million and dropped off Forbes magazine’s list of the 400 richest Americans. Nearly half that money — $150 million — went to a foundation named for them that must spend its last penny within 20 years of the last spouse’s death.

At age 84, in June 2014, Mr. Lenfest unexpectedly became the sole owner of the Inquirer, the Philadelphia Daily News and Philly.com after business partner Lewis Katz died in a plane crash days after they paid $88 million to buy the company from rival co-owner George Norcross.

Though the Lenfests lived a luxurious life with yachts, expensive cars and multiple homes, friends described them as down-to-earth. They spent much of their time at their house in Huntingdon Valley, Pa., which they bought for $35,000 in 1966. With no help, the Lenfests cooked for guests.

Harold FitzGerald Lenfest and his twin sister, Marie, were born in Jacksonville, Fla., on May 29, 1930. They soon moved to Scarsdale, N.Y., where their father worked in the shipping industry, and later to a farm near Lambertville, N.J.

Mr. Lenfest received a bachelor’s degree in economics from Washington and Lee in 1953, and two years later married Brooks. In addition to his wife and his sister, survivors include three children, Brook J. Lenfest, H. Chase Lenfest and Diane Lenfest Myer; and four grandchildren.

Mr. Lenfest served in the Navy and graduated from Columbia Law School in 1958.

He worked for a New York law firm before landing a job in 1965 with Walter Annenberg’s Triangle Publications, which owned TV Guide, Seventeen magazine, several TV and radio stations, and cable franchises.

In 1973, Annenberg decided to sell the cable assets. Mr. Lenfest, with the help of two investors, ended up buying the system in Lebanon, Pa.

“I was editorial director and publisher of Seventeen magazine and I had an office on Park Avenue. I had a good salary,” Mr. Lenfest recalled in 2000. “I left all that to work out of my basement for 12 years, not nationally known, not a good salary. I used to sleep on the sofa in Lebanon, because I couldn’t afford a hotel room.”

That one system in Lebanon eventually became Suburban Cable, the 11th-largest cable company in the country.

Mr. Lenfest expanded slowly at first. He grew the system in Lebanon, set up cable franchises in towns around Philadelphia and by 1981 the company had about 40,000 subscribers. The company acquired systems in and around San Francisco and pushed hard to expand in the Philadelphia area.

By the time Mr. Lenfest sold Suburban to Comcast in 2000, it had 1.2 million subscribers.