Peter Yarrow was born on May 31, 1938 in New York City. He learned to play both guitar and violin at a young age, and attended New York City's High School of Music and Art—now LaGuardia High School—before enrolling at Cornell University. He graduated from Cornell in 1959, with a bachelor's degree in psychology, and then moved back to New York City.
Yarrow intended to pursue a career in psychology, but quickly became involved in the Greenwich Village music scene. Although he knew Mary Travers and Paul Stookey, they didn't begin singing as a group until manager Albert Grossman pieced the trio together, seeing that they could be commercially successful.
Peter, Paul and Mary played their first show at Greenwich Village's Bitter End, and their first album was released by Warner Brothers Records in 1962. The following year, Yarrow wrote "Puff the Magic Dragon," which was based on a poem written in 1959 by Leonard Lipton, a friend of Yarrow's from Cornell. The song reached No. 2 on the Billboard 100 chart.
In the 1960s, Greenwich Village was a hotbed of issues, particularly civil rights and the Vietnam War, and Yarrow eagerly jumped into the fray of political activity. The group was at the forefront of the folk-protest movement, and they sang songs of social justice at the historic March on Washington, D.C. led by Dr. Martin Luther King Jr., as well as the Selma-Montgomery March of 1965.
The trio toured together for nearly 10 years, before breaking up in 1970 to pursue individual careers. Yarrow continued to write music, including Mary MacGregor's No. 1 hit, "Torn Between Two Lovers." Yarrow then earned an Emmy Award for the television special that was based on his hit song, Puff The Magic Dragon, which he co-produced along with two sequels. He even appeared in the initial TV movie as Jackie Paper's father.
Peter, Paul and Mary reunited for a concert in support of George McGovern's presidential campaign in 1972, and then again at a concert protesting nuclear energy in 1978. Shortly after, they resumed touring, and played nearly 50 shows a year, until Travers's death in 2009. Yarrow continues to perform with Paul Stookey.
Yarrow's commitment to political and social causes is largely inextricable from his music career. He has organized, produced and performed at political and charitable events since the 1960s, including the 1969 March on Washington, D.C. and the National Mobilization Committee to End the War.
In 2000, Yarrow founded Operation Respect, a nonprofit organization that aims to reduce school violence by teaching children tolerance and respect for diversity.
The organization developed the "Don't Laugh at Me" program, which uses music and video to teach conflict resolution to elementary and middle school students, and is distributed at no cost to schools.
Yarrow married Mary Beth McCarthy, the niece of the Democratic Senator Eugene McCarthy, in October 1969, and the couple had two children. They later divorced.