Carlson started his career as a psychotherapist and ran a stress management centre. He published his first book in 1985, but became famous with his 10th book, Don’t Sweat the Small Stuff…and it’s all Small Stuff. While Richard Carlson did not coin the term "Don't Sweat the Small Stuff," he was awarded a trademark for bringing it into American pop culture. The book was number one on the New York Times list for over 100 weeks. The Don't Sweat series is based on his earlier work presented in "You Can Be Happy, No Matter What: Five Principles to Keep Life in Perspective."