Professor James Callahan, or Jim, was one of the first people Lisa Lynch met in the summer of 2008 when she became dean of Brandeis’ Heller School for Social Policy and Management.

“I remember he just popped in my first day when my door was open,” Lynch said.

“He just came in and started talking, he said if I ever needed any help, he’d be glad to advise me.”

Callahan, who specialized in elderly care, was killed at the age of 74 on Oct. 12 after he slipped and fell under an MBTA commuter rail train traveling inbound at the West Newton rail station.

“We were all devastated and in a state of shock,” Lynch said of Callahan’s death.

“Jim would just come in out of the blue with a twinkle in his eye. His spontaneity would just make your day.”

Lynch said Callahan would bring her bouquets of flowers from his garden which he tended to in his spare time. “He liked to bring in Bleeding Hearts because he called them the official flower of the Heller school.”

Professor Michael Doonan (HELLER), who had received his doctorate from the Heller School and knew Callahan both as a professor and as a colleague, said Callahan brought the same enthusiasm to class that he brought to his personal relationships.

“He was incredible in his service to public policy, the classroom and everyone he came in contact with,” Doonan said. “To have all of those qualities is really rare.”

Doonan took a history of social policy class with Callahan when he was a student in 1996 and now, 14 years later, is the professor for that class.

“He passed it down to me and, whenever I was thinking of a change for that class, he would take me out to lunch,” Doonan said, adding he was scheduled to have lunch with Callahan this week.

Callahan, who was not teaching any classes at Heller this semester, had been a Brandeis faculty member for 25 years and received his doctorate from the university. Callahan also worked in state government as Secretary of Elder Affairs and Commissioner of Mental Health.

Callahan received his Bachelor’s degree from Holy Cross College before getting his Masters’ of Social Work at Boston College. Boston College later awarded him the School of Social Work’s award for dedication, integrity and commitment to the field of social work in 2003.

“He didn’t just tell you about his deep knowledge of history,” Doonan said. “He brought in his experience working for government and found a way to make understanding history important to understanding policy today and how to improve on policy for vulnerable populations.”

Lynch too said Callahan’s understanding of his field was “incredibly complex.”

“You can’t just say that he was a specialist in aging, he had a very holistic approach,” she said. “He had the view that the Heller School shouldn’t just have one person who specializes in aging, but that you need to think of it in a more integrated way, that aging crosses with poverty, health and family. For him, it wasn’t just in some box on the side.

“It gives you an idea of how broad a person he was,” she said.

Along with being a social policy historian, Callahan was also a Brandeis historian. When Lynch was organizing a celebration of the Heller School’s 50th anniversary last year, Callahan found a file of the “original founding documents” of the school in his house and donated them to the archives.

“He was just so considerate and helpful in that way,” Lynch said. “It’s hard to accept the fact that he won’t be popping into the office anymore.”