Paul Sprenger had a reputation for dusting off the difficult cases other lawyers didn't have the courage to litigate — and then winning them.

In his 50 years as an attorney, Sprenger became a thorn in the side of corporate America as he took on many Fortune 500 companies, including 3M, Cargill and PepsiCo. Supporters of his firm, Sprenger and Lang, call him a champion of employee rights because of his role in two important Minnesota cases about discrimination against women.

Sprenger, a Stillwater native, died unexpectedly Dec. 29 while snorkeling off a beach in Curacao with his wife and law partner, Jane Lang. He was 74.

After representing Shyamala Rajender, an assistant professor of chemistry, in a gender-discrimination case against the University of Minnesota in the 1970s, Sprenger was credited with opening doors to women for tenure-track positions at the university and changing the face of higher education. Sprenger discovered that no woman had been hired on a tenure track or granted tenure at the university in more than 60 years in engineering and the hard sciences.

"There was clearly this refusal of the federal government to take this case — and for him to take this on showed his dedication and a recognition of its importance," said state Rep. Phyllis Kahn, who was recruited for the Rajender case as a plaintiff intervenor.

Almost a decade later, Sprenger brought a landmark sexual-harassment case against the Eveleth Taconite Co. In 1988, he filed a class-action lawsuit on behalf of miner Lois Jenson and other female workers who had been subjected to verbal and physical harassment at a mine on northern Minnesota's Iron Range.

The case became the basis for the 2005 movie "North Country," in which Woody Harrelson played a character based on Sprenger.

Larry Schaefer, a former managing partner at Sprenger's firm, said Sprenger acted as a mentor and friend to him during their 13 years together. Sprenger understood the power of class-action lawsuits to make real, systematic change, Schaefer said, and he used them better than anyone.

Sprenger's fearlessness made him a "transformative figure in law," Schaefer said.

"He would chart that strategy and never waiver from it — and believe me, many people would have," Schaefer said. "I never saw him back down."

Outside of his precedent-setting cases for women, minorities and older workers, friends said Sprenger had a sense of humor and charisma.

Sprenger met his future wife when they were on opposites sides of a case involving black employees of Burlington Northern Railroad and had to negotiate a settlement.

"He combined an incredible personal charm with a dogged conviction on behalf of his clients," Schaefer said.

Later in life, Sprenger and Lang became philanthropists, founding the Atlas Performing Arts Center in Washington, D.C. The center sparked a revitalization of the whole "Atlas" district and was added to the National Register of Historic Places.

His son, Steven, bought the firm in 2000, but Sprenger and Lang continued to do legal work. Steven Sprenger closed the Minneapolis office in 2009 and worked from its D.C. branch.

Besides his wife and son, Sprenger is survived by daughters Heidi and Sara; stepchildren Jessica Lang and Benjamin Alamar; 14 grandchildren, and one great-grandchild.

In lieu of flowers, the family suggests contributions be made to the Atlas Performing Arts Center (Atlasarts.org) or Tregaron Conservancy (Tregaronconservancy.org) in Sprenger's memory. A memorial in Minneapolis will be planned soon.

Liz Sawyer • 952-746-3282