David A. Jones, who with a partner built Humana from a single nursing home into a health insurance behemoth, died on Wednesday at a rehabilitation facility in Louisville, Ky. He was 88.

A company spokesman said the cause was complications of multiple myeloma.

In Louisville, a city known mostly for thoroughbred horses and bourbon, Mr. Jones and Wendell Cherry, a friend and fellow lawyer, brought health care assertively into the foreground.

In the 1960s, they built the nation’s largest nursing-home chain. After selling the homes in the early ’70s, they created Humana, one of the biggest hospital chains in the United States. And in the 1990s, after Mr. Cherry’s death, Humana spun off the hospitals as Mr. Jones led the company’s drive into health insurance. It is now the fourth-ranked company in the industry.

Over more than 40 years at Humana, Mr. Jones became an influential business and civic leader and a confidant to the Senate majority leader, Mitch McConnell of Kentucky. Mr. Jones and his family have been strong supporters of Mr. McConnell’s political career, Politico has reported, and Mr. McConnell, a Republican, secured millions in funding for a 4,000-acre park in Louisville, Parklands, which was championed by Mr. Jones.