Lawrence Albert Siebert was born in Portland, Oregon, to Donald and Mildred Siebert on January 21, 1934. Raised in Portland, he graduated from Grant High School in Northeast Portland before attending Willamette University in Salem, Oregon. There he graduated from the school with a bachelor of arts degree in psychology. Siebert earned his master's and PhD in clinical psychology from the University of Michigan.

He was an ex-army paratrooper, joining for a short time at the end of the Korean War. As adjunct professor, he taught management psychology seminars for over forty years at Portland State University. He was the author of several books on resiliency and survivor traits.

Siebert was a guest on radio and television interviews and call-in shows such as NPR, CNN, Oprah, and NBC's Today Show, and was featured in magazine articles in USA Today Weekend, Family Circle, Men's Fitness, Prevention Magazine, Good Housekeeping, Harvard Business Review, and Dr. Andrew Weil's Self-Healing Newsletter,. His "How Resilient Are You?" quiz has been reprinted in many publications.

He was frequently quoted in newspapers articles and other mass media as an expert on issues of workspace stress and resilience.

Siebert lived in Portland with his wife Molly and spoke to business, government and military leaders on developing resiliency skills. Siebert died on June 25, 2009, in Portland at the age of 75 from colon cancer.