Several hundred friends and family members gathered in Brentwood, Calif., Saturday morning to celebrate the life of UC Berkeley alumnus and Peace Corps volunteer Nicholas Castle, who died of a sudden illness in early February.

Family and friends remembered Castle’s smile, which appeared throughout a photo slideshow depicting his life: as a baby grinning broadly, as a young man happily conquering the waves on his surfboard and as a UC Berkeley student confidently smiling with his parents in front of South Hall.

“How can you take such a beautiful life and put it into words?” said Castle’s brother Joe at the commencement of the memorial service.

Castle, who graduated from UC Berkeley in 2012 with a degree in political science and comparative politics, had taught university-level English in China’s Guizhou province with the Peace Corps since August.

Castle’s love for teaching preceded his role as an English teacher in China. He spent more than six years as a tutor and mentored countless others in his hometown of Brentwood.

“Whenever our girls had a question about anything, they’d call him,” said Jolene Conder, a family friend whose two daughters Castle mentored. “He was real-life proof to them that anything was possible.”

Castle also built lasting relationships with his students in China, who would often eat dinner with him and affectionately referred to him as “Mr. Sunshine” because of his smile, according to Peace Corps regional director Helen Lowman, who read a letter expressing President Obama’s condolences.

Eric Behne, Castle’s high school friend, remembered that his first impression of Castle was that he was “extremely smart” and “good at everything,” but his fondest memories are the countless hours the two spent listening to the Beatles’ music and classic rock. Behne said that when he recalls his high school years spent with Castle, he can barely remember being in class at all.

Family and friends were unsurprised to hear that Castle would be serving in the Peace Corps, as he had spent a great deal of his childhood serving in his local community. Jami Palladino, another family friend, told of the way in which Castle had often helped out in her husband’s vineyard, pulling weeds and helping customers select fruit to purchase.

“I was so proud of the man he had become,” said Castle’s father, David. “I was so impressed with his intelligence, his compassion and his love for humanity.”

David Castle’s lasting memory of his son is of when the two visited a Vincent van Gogh exhibition at the de Young Museum, where he remembers his son standing in front of “The Starry Night” in quiet contemplation.

“That memory reminds me of a lyric once written about that painting,” he said, referring to “Vincent” by Don McLean. “‘The world was never meant for one as beautiful as you.’”