Ben du Pont and his business partner Don Wirth have agreed to purchase the 500-acre DuPont Country Club and will invest $18 million in upgrades, du Pont said Thursday.

"My life's ambition was not to own a country club," said a laughing du Pont, who like Wirth is a former manager at the chemical giant that du Pont's ancestors founded in 1802 and built into the most valuable U.S. company in the mid-1900s. Golf courses were "on my 'do not own' list," du Pont told me. But as the club — which includes three golf courses, more than two dozen tennis courts, and a 130,000-square-foot clubhouse just up the road from du Pont's childhood home outside Wilmington — sat on the market attracting interest from investors and developers, "I just didn't want an out-of-state private equity firm owning 500 acres in the heart of Wilmington. How would that have ended well?"

It's "an ideal outcome," said Edward D. Breen, chief executive officer of the course's seller, DowDuPont Co., and of predecessor DuPont Co., which had been trying to sell the club under pressure from investors who saw it as a symbol of overly entrenched management since before its merger into Dow Chemical Co. last year. "From the beginning, DuPont has maintained our commitment to identifying a community-minded buyer to continue to operate the facility as a club without residential development. As local investors with deep Delaware roots, Ben duPont and Don Wirth are the perfect buyers," Breen added.

The sale price was not immediately disclosed. Du Pont said M&T Bank, successor to the family's former Wilmington Trust Co., is helping finance $18 million in planned improvements. Immediate priorities include improved food service, "the fastest internet you can get," and a smartphone app "where you can book a tee time and tennis lessons for your kid," du Pont said.

After that, the partners propose a 17,000-square-foot indoor fitness facility for "cardio, yoga, weights, all the stuff you and I should be doing," du Pont added. The partners plan to truncate the Montchanin course, currently the shortest of three courses at the club, while leaving the two others at 18 holes. They want to add a heated, indoor driving range, "so you can hit golf balls in the driving rain in February while you're drinking a beer with a fireplace behind you." No state or charitable-foundation money is involved, du Pont added.

To realize their ambitious plans for the club, Du Pont and Wirth, a former DuPont Co. supply-chain vice president under former CEO Ellen Kullman and the father of the club's current tennis program head, need to boost membership. The current rolls include around 1,700 families, down almost two-thirds from 20 years ago, du Pont said. Membership includes an initiation fee, currently $5,000 but available with significant discounts, and a monthly fee of under $100.

Du Pont says the club should be affordable to people making in the upper-five-figures a year. "We are transitioning the club to being more family-friendly and more sports-oriented," he told me. "If membership rises, and we expect it will, we begin phase two: athletic facilities, a place to play volleyball and other team sports."

He sees Philadelphia's Union League club, which has boosted membership while adding business-oriented and public-service programming, golf courses, and restaurants in recent years, as an example of how traditional clubs can gain relevance and interest even as traditional sports participation has waned.

Besides putting the courses up for sale, DuPont has sold off its three million-square-foot former Wilmington headquarters, professional theater, and other assets collected in the early 1900s as part of DuPont's efforts to lure professional managers, scientists, and engineers to northern Delaware during and following its World War I-era expansion. Buccini/Pollin Group bought the hotel and has realigned the menu in its fancy Green Room toward family fare.

The headquarters-city trappings had become a target of criticism from hedge-fund investor Nelson Peltz and other shareholders concerned about the company's low earnings and share-price growth in recent decades — and by some company insiders who worried DuPont had become a slow-moving bureaucracy more successful at making managers rich than executing tough product and sales decisions in difficult world markets.

Neighbors of the golf courses, including adjoining neighborhoods of single-family homes as well as the nearby "chateau country," where du Pont's cousins and other wealthy Wilmingtonians own mansion estates, had worried the company might sell the courses to developers. That would end the club's role as a wide, green buffer between the busy U.S. 202 corridor and the Brandywine Valley attractions built around du Pont family estates such as Longwood Gardens, Winterthur, Hagley, and Mount Cuba. Builders have proposed redeveloping former DuPont Co. offices south of the complex as retail and housing areas. Buccini/Pollin is building apartments in part of the former DuPont headquarters building on Wilmington's Rodney Square.

Given the concerns over the area's future, the du Pont/Wirth deal is "a hole in one," State Sen. Greg Lavelle, leader of the Republican minority in Dover, said in a statement.

Du Pont, a former DuPont Co. manager who leads the private equity firm Chartline Capital Partners, is also a leader in Zip Code Academy and other tech business development efforts in Delaware. His father, Pierre S. "Pete" du Pont IV, is a former Delaware governor and namesake of the modern DuPont Co.'s corporate architect, Pierre S. du Pont II, who built Longwood Gardens. Du Pont's mother, the former Elise Wood, is an heir to the Wawa fortune and a longtime University of Pennsylvania trustee. Their home, Patterns, and the elder du Pont's childhood home, Brantwyn, later a DuPont Co. conference center, are located just south of the country club.