Paul was raised in the lobster fishing town of St. Andrews-by-the-Sea in New Brunswick. In 1960, Paul was a member of the Kindness Club, founded by Aida Flemming in New Brunswick. After trappers killed one of his beaver friends, Paul set out, at the age of nine, to confiscate and destroy leg-hold traps. He was also known to disrupted deer and duck hunters, and to prevent other boys from shooting birds.

Over the years, Paul has exhibited a remarkable diversity in his activism. Aside from being a co-founder of Greenpeace in 1972 and Greenpeace International in 1979 and founder of Sea Shepherd in 1977, Paul was a Field Correspondent for Defenders of Wildlife between 1976 and 1980. He was a field representative for the Fund for Animals between 1978 and 1981, and a representative for the Royal Society for the Protection of Animals in 1979. He co-founded Friends of the Wolf in 1984 and the Earthforce Environmental Society in 1977. Paul's first affiliation with the Sierra Club was in 1968 and he has remained a Sierra Club supporter ever since. In April 2003, Paul was elected to the National Board of the Sierra Club USA. He will be a director until 2006.

Paul majored in communications and linguistics at Simon Fraser University in British Columbia. He has lectured extensively at universities around the world, and was a professor of Ecology at Pasadena College of Design from 1990 through to 1994. Paul also was an instructor in UCLA's Honors Program for 1998 and 1999. Currently, Paul is a registered speaker with the Jodi Solomon Speakers Bureau of Boston, and regularly gives presentations at colleges and universities in the United States, and at special events throughout world.

On the political front, Paul has run for Member of Parliament for Vancouver Centre in the Canadian Federal elections. He ran twice for the Green Party. He also ran on the Green Party ticket for Vancouver Parks Board in 1987 and for Mayor of Vancouver in 1995.

Paul has received many awards and commendations over the years. In 1996, Paul was awarded an honorary citizenship to the French town of St. Jean Cap Ferrat. Previous to that he was made an honorary citizen of the Florida Keys in 1989. Other awards include Toronto City TV's Environmentalist of the Year Award for 1990, the Genesis Award in 1998 and he was enrolled in the U.S. Animal Rights Hall of Fame in 2002. He was also awarded the George H. Bush Daily Points of Light Award in 1999 for his volunteer efforts with conservation activism. He was chosen by Time Magazine as one of the environmental heroes of the 20th Century in the year 2000.