Renowned Yale historian David Montgomery, a leader in the field of United States labor history, died from a brain hemorrhage Friday at Thomas Jefferson University Hospital in Philadelphia. He was 84.

Throughout his life, Montgomery pursued a longstanding interest in labor affairs through both hands-on experience and academic studies. He worked as a machinist in New York and St. Paul, Minn. shortly after graduating college, and continued to support the efforts of labor unions during his later career as a historian. Montgomery’s experiences as a laborer shaped his academic pursuits and helped him to redefine the focus of labor history in academia.

“David believed to his bones that history showed that working people were capable of managing their affairs themselves, using their own resources,” said Dana Frank GRD ’88, a professor of history at the University of California at Santa Cruz who did graduate work with Montgomery. “He had a boundless enthusiasm for the millions of stories that showed working people’s creativity and resourcefulness.”

Montgomery joined Yale’s History Department in 1979 after a 14-year career in the University of Pittsburgh’s history department, which he chaired from 1973 to 1976. Before entering academia, Montgomery organized labor protests for unions in St. Paul during the McCarthy era, and was ultimately blacklisted by a number of industrial companies in Minnesota for those efforts. Montgomery continued to support labor unions during his tenure at Yale, and helped organize members of the University’s Locals 34 and 35 in the 1984 Yale clerical workers strike.

Scholars who worked with Montgomery said he was a “pioneer” in the field of labor history, and helped bring the focus of the field to individual workers.

Jim Green GRD ’72, a professor of labor history at the University of Massachusetts at Boston, said it was Montgomery’s early work as a machinist that made him so attuned to the concerns of individual laborers as an academic. Montgomery approached his scholarly work as “someone working on the inside with academic tools,” said Green, who met Montgomery while pursuing a graduate degree in history at Yale.

“His scholarship was democratic in the sense of his instinct to look into the lives of ordinary people and to see them as people making their own history,” Green said. “He went right down to the level of a shop floor to see how people were working.”

During his time at the University of Pittsburgh, Montgomery drew students from across the country to study labor history, and helped the school emerge as a hub for “new labor history,” said Shelton Stromquist ’66, a history professor at the University of Iowa and a graduate student of Montgomery’s in the 1970s. Montgomery’s work had an “enormous influence” on the formal study of labor, Stromquist said ­— emphasizing power in the labor process “from the bottom up” and reducing the traditional focus on trade unions or labor leaders.

Jennifer Klein, a history professor at Yale, said Montgomery exemplified the ideal of the “scholar-activist.”

“I think there’s this notion that you do research and it’s remote and abstract and the people you’re writing about are subjects, but he always was in solidarity with them,” Klein said. “He had such a commitment to the political and social importance of the work.”

In the classroom, Montgomery was known both for his deep-rooted interest in his subject and his compelling lectures. Green said Montgomery was skilled at rousing groups of people with his “old-fashioned oratorical style” — from students in a lecture hall to protesters at a rally.

Montgomery’s son, Edward, an economics professor and dean of Georgetown University’s Public Policy Institute, said both he and his father shared a focus on “the things that impact ordinary men and women’s lives.”

“As for his family, we respected his integrity, admired his intellect and loved his heart,” Edward Montgomery said. “We will miss him dearly.”

David Montgomery is survived by his wife, Martel, his sons, Edward and Claude, five grandchildren, a brother, Daniel, and a sister, Virginia.