For former Merrill Lynch CEO E. Stanley O’Neal, the fall from financial power was fast. And while colleagues have blamed his go-it-alone approach, friends from his days at Harvard Business School remember a different Stan.

O’Neal’s classmates, professors, and colleagues expressed admiration of the financier’s friendliness and insight during his time as a student at the Business School (HBS).

“[What] impressed me most about him was that he had a tremendous interpersonal sensitivity, well beyond what students his age typically have,” said Tony Hain, a professor at Kettering University who taught O’Neal as an undergrad.

O’Neal served as CEO of the world’s largest brokerage for six years before retiring on Tuesday. After the company posted its biggest quarterly loss in its 93-year history, the board lost confidence in him.

“He seemed to understand the motivation about why people did things. He grew up in two worlds: the one he came from and the one he was in. He referenced from one back to the other as he moved forward in life,” Hain said.

Hain later wrote a recommendation when O’Neal applied to HBS, where O’Neal was one of a handful of black students in his class.

O’Neal, who graduated in 1978, was vice president of the Afro-American Student Union. He attended HBS at a time of transition for black students.

In 1976, the Business School faculty voted to drop special minority admissions procedures, arguing that they were no longer needed to ensure enrollment of black, Hispanic, Asian-American, and Native American students.

Only a few years earlier, the student union had accused the FBI of trying to infiltrate their organization with an informer. Black student groups at other elite universities had also complained of attempted FBI infiltration.

“He should be credited as a hero as one of the few black men to get through HBS at a time when there were few black people at any of the Harvard schools,” said classmate Richard A. Candee Jr.

O’Neal was not the “kind of active talker that other HBS students were, but he was very thoughtful when he entered into discussions,” Candee added. “Stan was very serious.”

Those who knew O’Neal seemed surprised by the characterization of O’Neal as a loner in media reports since his ouster. The New York Times described O’Neal as “an aloof, calculating man who during his 20 years at the firm has made few friends.”

Candee said HBS places a large emphasis on collaboration, and said he always enjoyed working with O’Neal.O’Neal was not the “kind of active talker that other HBS students were, but he was very thoughtful when he entered into discussions,” Candee added.

“Stan was very serious,” Candee said.

Hain also questioned the accuracy of the characterization. O’Neal and Hain became colleagues at General Motors upon O’Neal’s graduation from the Business School. Hain said that O’Neal was well regarded at the company.

“To accomplish what he did,” Hain said, “he couldn’t have gotten there without knowing what makes people tick, and being able to relate between business and people.”

“[What] impressed me most about him was that he had a tremendous interpersonal sensitivity, well beyond what students his age typically have,” Hain said.

Peter F. Grossman, another classmate, remembered O’Neal as a bright, thoughtful student.

“Stan’s transformation and development wasn’t just that of a black man in a white world, but of a man coming out of the manufacturing environment and entering the world of finance and Wall Street,” Candee said. “His transformation was one of a guy who was keen to learn about the world in which he worked.”