BEFORE HIS ASCENT to attorney general of Delaware and the status of a front-runner for the state's governorship in 2016, Beau Biden was the "moral compass" of his University of Pennsylvania fraternity, a frat brother said Sunday.

Joseph R. "Beau" Biden III, the vice president's son and a rising political star who died Saturday from brain cancer, was beloved among his fellow members of Psi Upsilon, a fraternity that was embroiled in controversy while he was there.

In interviews Sunday, his friends in the fraternity - known on campus as "Castle"- recalled a humble, compassionate man who used his sense of humor and sharp intellect to build friendships.

"Despite being such a big name and persona, he always made you feel like you were the most important person in the room," said Eric Garrard, Biden's sophomore-year roommate in the frat house.

Garrard remembered arguing with Biden over politics, during which Beau's "well-thought arguments" sometimes even persuaded him from his Republican beliefs.

"He used to love the fact that I was a Republican," Garrard said. "He liked a challenge."

Garrard, who works in his family's steel-manufacturing business in Pittsburgh, became friends with Biden early in freshman year. They lived in the same hallway in the Quadrangle, an ornate Gothic structure linking Penn's three oldest dorms.

Upon meeting for the first time, they instantly settled the matter of their opposing political views.

"He introduced himself in the Quad and said, 'Hey, I'm Beau,' and I said, 'Hey, I'm a Republican so you don't want to meet me,' " Garrard recalled.

Biden joked in return, " 'No, you're an a------, and you're probably right.' "

The two laughed and "just became instant friends," Garrard said.

Unusual for a fraternity brother, Beau never drank or smoked, according to three classmates.

Biden, who graduated from Penn in 1991, was a member of the fraternity when it was shut down in 1990 for five years after 10 members were arrested in the kidnapping of a member of a rival fraternity. The 10 members received probation, and Biden was not among those arrested. The university disciplined 22 members, whose names were not released.

"Beau knew at a very young age that he wanted to be a public servant, and he was not swayed by peer pressure," fraternity brother Evan Haymes said.

Haymes, who was a junior when the freshman Biden entered Castle, served as his "big brother" or mentor.

"He was somewhat of a moral compass," said Haymes, a venture capitalist in New York. "Not that he ever intended to be, but it was the result of his integrity."

Thomas Frayne, a 1986 Penn graduate who hung around the Castle house as a party DJ, also noticed Biden's underage sobriety.

"What was remarkable about him was that he was in college, and he didn't drink a drop until he was 21," Frayne said.

Long after his father's ascent to the vice presidency and his own entry into politics, Biden remained a constant friend to his Penn classmates, they said.

In 2012, Garrard surprised Biden by watching him give a speech to a group of Democratic supporters in Kennett Square.

Amid nearly 500 hardcore Democratic supporters, Biden noticed him and said, " 'I just want you [all] to know that my Republican roommate is here.' "

Garrard compared the speech to Biden's emotional introduction of his father at the 2008 Democratic National Convention, at which he spoke about the auto accident that killed his mother and sister.

"He was able to command an audience," Garrard said.

Biden's classmates said that his ability to overcome immense personal tragedy seemed to deepen his empathy for others.

"It was through tragedy as a young person - [losing] his sister and his mother - [that] I think added to his sensitivity," Garrard said.

"Beau was an incredibly sensitive human being who could listen," Garrard said.

Despite their differing political views, Garrard saw in Biden a candidate who could bridge the increasingly polarized gap between the two major political parties.

"He may have been one of the only leaders out there that could have broken this barrier of red and blue," Garrard said.

After finding out about Biden's death, Garrard remembers saying to a friend, "I really thought he would have changed the world."

Although his father, the long-term senator from Delaware who became vice president, cast a long shadow, Biden never used his family's political clout to his advantage, Penn friends said.

Haymes remembered riding home on the train with Beau from a speech that Joe Biden had made in Washington, D.C. They were running late to Union Station, and Haymes asked his friend, "Would Amtrak ever hold a train?"

While admitting that Amtrak had done such a courtesy for his father, Beau said: "Not for me."

In college, Beau Biden even avoided political confrontation when it came front and center. During an interfraternity billiards tournament, he made it to the championship representing Castle. His opponent, George Herbert "Chip" Walker IV, representing St. Anthony's Hall, or "St. A's," was a second cousin to future President George W. Bush. Their match never became more than members of two frats playing pool.

"One might view this as a huge political battle, but it wasn't Beau's perspective," Haymes said, adding, "It was all in good fun."

The devastating effect of Biden's brain cancer evaded most of his friends, who never anticipated his early passing.

"If you met him as recently as nine or 10 months ago, he was lanky, athletic, and that's what makes this such a total and complete shock," Haymes said.