Coleman was born in Norfolk, Virginia, grew up in Decatur, Illinois and graduated in 1965 from MacArthur High School. He studied anthropology and zoology at Southern Illinois University at Carbondale, and psychiatric social work at the Simmons College School of Social Work in Boston. He did further studies in doctoral-level anthropology at Brandeis University and sociology at the University of New Hampshire. Coleman taught at New England universities from 1980 to 2004, also having been a senior researcher at the Edmund S. Muskie School of Public Policy from 1983 to 1996, before retiring from teaching to write, lecture, and consult.
Coleman writes on popular culture, animal mysteries, folklore, and cryptozoology. An editor of the Skeptical Inquirer said, "among monster hunters, Loren's one of the more reputable, but I'm not convinced that what cryptozoologists seek is actually out there." He has appeared on television and radio interviews about cryptids. He has written articles and books on cryptozoology and other Fortean topics. He was a publicity consultant on The Mothman Prophecies.
Coleman has carried out fieldwork throughout the United States, Canada, and Mexico, regarding sightings, trace evidence, and Native peoples' traditions of Sasquatch/Windigo/Bigfoot. He has written on Yeti and Bigfoot expedition sponsor Tom Slick and appeared on NPR discussing the death of Grover Krantz. Coleman has won awards for this documentary and literary work.
Paraview Press introduced a series of books, "Loren Coleman Presents" in 2004. Coleman wrote introductions to volumes in the series.
Coleman contributed to the exhibition "Cryptozoology: Out of Time Place Scale," shown at Bates College Museum of Art (June 24 - October 8, 2006) and at the H & R Block Artspace at the Kansas City Art Institute (October 28 - December 20, 2006). He delivered the keynote address, "An Introduction to Cryptozoology," at the symposium at Bates College in October 2005, and gave a similar talk at the American Museum of Natural History in 2007.
Coleman is also a contributor/coauthor to the 2006 Bates exhibition catalogue and book, Cryptozoology: Out of Time Place Scale (JRP/Ringier Books, Switzerland, 2006). He also wrote the essay “Cryptids” for Alexis Rockman. (Monacelli Press, 2005).
Coleman established a Cryptozoology Museum in 2003 in Portland, Maine. The first downtown location for the museum opened in November 2009, occupying the rear of The Green Hand Bookshop, a Portland general used bookshop specializing in science fiction, fantasy, and other forms of Gothic fiction. On October 30, 2011, two years after moving onto Congress Street, it re-opened in a much larger space around the corner at 11 Avon Street, although it is still located in the Trelawny Building. A newly built museum, located at Thompson's Point, Portland, Maine, is scheduled to open in mid 2016.
Coleman has a master's degree in psychiatric social work and was a consultant for the Maine Youth Suicide Program for nearly a decade. He authored several manuals and trained over 40,000 professionals and paraprofessionals statewide. A specific concern continues to be cases of murder-suicide among the young as well as the possibility of clusters (e.g., teen suicides, school shootings, workplace violence, and domestic terrorism) and the influence of media coverage, leading to his writing the books Suicide Clusters (Boston: Faber & Faber, 1987) and The Copycat Effect (New York: Simon and Schuster, 2004). He has been called on for statements in the aftermath of school shootings and how best to respond to the problem, mostly by the Canadian media.
Coleman has been married three times, from 1968 to 1978, from 1980 to 1995, and from 2013 to the present. He has three sons and resides in Portland, Maine.