Berkeley College senior Andrew Kroon couldn’t resist a bald head.

Dan Guando ’04 said he wasn’t one of Kroon’s best friends, but that didn’t matter – Kroon was friendly to everybody. Every time Kroon saw Guando and his bald head, Kroon would run over, grab Guando’s cheeks, and passionately kiss his scalp.

“He always knew how to lighten the mood, how to make everyone feel loved,” Guando wrote in an e-mail. “He was one of the funniest guys I’ve ever met, and one of the warmest. Irreplaceable.”

Kroon, who was 24 and slated to graduate in only a few weeks, was found dead Saturday in his room at the Taft Apartments. Yale College Dean Peter Salovey said Sunday the death was accidental, and New Haven Police said Monday they currently believe the death was caused by an overdose, declining to elaborate further.

Police said they are awaiting verification in the form of a toxicology report from the State Medical Examiner’s Office.

Friends remembered Kroon as an environmental activist, passionate about helping others, enthralled with the Amazon after multiple visits to Brazil, and up for just about anything.

Max Ventilla ’02 SOM ’05 roomed with Kroon off campus in 2002. He said Kroon immersed himself in environmental activism on campus. He was dedicated to improving campus recycling, helped spark the Berkeley sustainable food initiative, and still managed to play pranks with the Pundits and frequent the party scene.

“He was a rare mix of someone who was incredibly fun but also serious about the things he was dedicated to,” Ventilla said. “There aren’t that many people who die at his age having accomplished something, but he was pretty fully formed … He was incredibly fun and casual and an impressive, formidable person.”

Kroon was born in New Jersey to a large, Irish Catholic family with deep roots at Yale. Two of Kroon’s brothers, Stephen ’05 and Michael ’06, currently attend Yale, and his father, an alumnus, made a major contribution to the Yale School of Forestry and Environmental Studies in 2004, enabling the school to finance its new building on Science Hill.

Kroon never lost sight of his family’s commitment to the environment, chairing the Yale Student Environmental Coalition as a sophomore.

“His environmental conscience was absolutely staggering in scope,” Berkeley Master John Rogers said. “His commitment to making the world better knew no bounds.”

Two years ago Kroon co-authored a report about sustainability issues on campus that Salovey and Univerisity President Richard Levin credited with increasing Yale’s awareness of environmental consumption and contributing to University policy.

“That report was very influential in helping to establish the kinds of sustainability policies and organized effort around sustainabiliy that we see on campus today,” Salovey said. “Andrew Kroon is somebody who leaves a very concrete legacy on this campus. A cause he was committed to produced concrete actions taken by the university.”

Michael Kroon emphasized the global scope of his brother’s passions and interests.

“It’s still too soon to even fathom the intense loss we have all just suffered, but I am certain that every creature on this planet has lost as dearly upon his death as we all gained upon his birth,” he wrote in an e-mail.

A Latin American Studies major, Kroon made several trips to Brazil, where he did environmental work in the Amazon. Friends said he loved Brazil and planned to return during the summer and possibly the fall before attending the Yale School of Forestry.

“He was more grown-up, more mature than most students,” Latin American Studies professor Enrique Mayer said. “He was more like a graduate student than like someone of his age. He did a lot on his own.”

In everything he did, Kroon was independent and unconventional, friends said. His looks stood out — he was big and bearded, a flashy dresser, and was engaged in a long-running contest with a friend to see who could wear the most pink.

Occasionally, Kroon’s distinctive appearance got him into awkward situations.

Once, visiting friends in Vanderbilt, someone called the police to complain about a homeless man in the building. The police arrived and Kroon had to convince them that he was a Yale student. Kroon wandered down to the suite that had lodged the complaint and, with his characteristic sense of humor, started begging for money.

Orijit Ghoshal ’06, one of Kroon’s Vanderbilt friends, said the incident was typical of his easygoing nature.

“Even if he didn’t have a smile on his face, he was always putting a smile on someone else’s face,” Ghoshal said. “That’s the best way to remember him. He had a way of putting everyone else at ease.”

But friends and acquaintances said finding a single adjective for Kroon is impossible. Few who met Kroon ever forgot him.

“Andrew was distinctive in every possible way,” Rogers said. “He struck a unique figure on campus that made him hard to miss. He just was Andrew Kroon.”

The Kroon family has requested donations be sent to YSEC in lieu of flowers.

— Alexandra Adler contributed to this report.