Kai Zinn was born in Berkeley, California, but grew up in Los Alamos, New Mexico. His father, now retired, was a chemist working on weapons research; his mother, who came to the United States from Germany after World War II, teaches German. Zinn had two brothers, but one was killed when he was fourteen. During high school, Zinn became an Explorer Scout and began to engage in outdoor activities like rafting, climbing, skiing, hiking. Zinn decided to attend the University of California at San Diego, where Paul Saltman inspired him to major in chemistry. During his last year in college, Zinn worked on an independent study with Jack Kyte. After graduation Zinn had planned to travel, but he fell at Yosemite National Park and broke his leg, so he ended up back at Kyte's lab for a month or so during that summer. Then he spent a year just traveling, visiting Nepal, Thailand, and the Virgin Islands. During his travels he picked up giardia and was ill for several months. Kyte helped persuade Zinn to go to Harvard for his PhD. There he worked on SV40 in Mark Ptashne's lab. While at Harvard, Zinn and Pamela J. Bjorkman, who was working on HLA (histocompatibility locus antigen) in Don Wiley's lab. met and married. Zinn next moved to Tom Maniatis's lab to work on interferon. After that, tired of interferon, Zinn moved to Corey Goodman's lab. Pamela stayed another year at Harvard, finally finishing the structure of HLA. After joining Zinn in California, Pamela discovered that she was pregnant with their son Leif. Zinn finished his postdocs at Stanford and Berkeley and then accepted a job at California Institute of Technology, where he is now an associate professor. He continues to publish, teach, read novels, work less then he would like on the bench, and spend time with his son, Leif, his daughter, Katya, and his wife.