Eugene Gaer, a 39-year Manhattan litigator and longtime health care lawyer who chose law as a second career, died on July 7.

He was 74 and suffered from a brief illness, said friend and former colleague Dorothy Heyl, general counsel and chief compliance officer at the investment advisory firm Prima Capital Advisors.

Known as a “lawyer’s lawyer” who “just had this fascination with the law,” Gaer began his legal career in 1978 as an associate at Rosenman Colin Freund Lewis & Cohen (now Katten Muchin Rosenman), Heyl said. In 1987, he left the firm to become general counsel at FOJP Service Corp., a health care facility-focused insurance and risk management advisory services company. He used that experience when he opened a solo practice in the 1990s—a practice he continued into this year.

Before his decades of lawyering, Gaer was an accomplished historian and college professor, developing a passion he never left behind, Heyl said.

He taught history in the 1960s at West Liberty University in West Virginia and earned a master’s degree in history from Harvard University as a Woodrow Wilson Fellow. In the 1970s, he taught history at Roosevelt University in Chicago and pursued, though never completed, a Ph.D. in European intellectual history from the University of Wisconsin and the University of Chicago.

His grounding in the subject later informed his law practice and life.

“He had an incredible memory and just always a fascination with information,” said Heyl, who met Gaer when they were associates at Rosenman Colin in the 1980s. “He had an extreme attention to detail, and he remembered anecdotes about people’s lives. It seemed like he knew more about my life than I did.”

Joel Sternman, another former colleague of Gaer’s from the Rosenman Colin years, said, “Gene was scholarly in his approach to legal issues. He wasn’t just looking to get an answer and make a simple argument that was supported in the law. He was kind of a teacher. He wanted to teach judges, he wanted to teach his adversaries, he wanted to teach his colleagues.”

Gaer was born in Milwaukee in 1942. After his years of studying and teaching history, he attended Columbia Law School, bringing him to New York City, where he lived the rest of his life. He graduated from Columbia Law in 1977, then served as a clerk to Court of Appeals Associate Judge Jacob Fuchsberg before joining Rosenman Colin.

He served as a judge for the New York Metropolitan Transportation Authority in the 2000s, and he was a longtime member of the New York City Bar Association, according to Heyl. He chaired the association’s State Courts of Superior Jurisdiction Committee from 1993 to 1996, and over the years served on its State Affairs Committee, the Civil Court Committee, the Health Law Committee, the Judiciary Committee and the Federal Legislation Committee.

Sternman, a Katten Muchin Rosenman partner since the 1970s, recalled on Tuesday his friend and former colleague’s diligence and success during several years at the firm in the 1980s. In particular, he remembered Gaer’s fight and moxie in defending the First Amendment rights of Yevgen Fromer, an imprisoned Orthodox Jewish man whom New York state had put in solitary confinement because he refused to trim his long beard.

Taking the matter pro bono, Gaer argued for his client’s First Amendment right to honor his religious beliefs, and he produced a Hasidic scholar’s lengthy volume that included passages on the religious meaning of wearing the beard untrimmed.

Southern District Judge Charles Stewart ordered Fromer released from isolation without making him to trim the beard, and Gaer later prevailed in an appeal to the U.S. Court of Appeals for the Second Circuit, Sternman said. (Later, though, the standard of review changed, and, while Gaer was no longer on the case, Fromer ultimately lost the battle.)

Gaer, who never married, is survived by his brother, Marvin Gaer, and sister-in-law, Eleanor Gaer, of Cherry Hill, New Jersey, and their sons, Arthur, Joseph and Herschel Gaer.

Contributions in Gaer’s name can be made to Hadassah Medical Center of Jerusalem, Congregation Ohab Zadek of New York, or a charity of the donor’s choice, Heyl said.

A memorial for Gaer’s family, friends and former colleagues will be held Sept. 12 at 6 p.m. at the 26 Broadway offices of Schlam Stone & Dolan in Manhattan.