Casey Anderson was born August 20, 1975 in East Helena, Montana, and was raised there. He is a fifth generation Montanan and was interested in animals from an early age, causing him to be nicknamed "the animal magnet" as a child. He graduated from Montana State University in Bozeman, Montana in 1995 with a degree in wildlife biology.

Anderson has been involved in film and television production since the 1990s. He worked as an actor, crew member, animal trainer/wrangler, and/or consultant for several programs produced by syndication company Associated Television International (ATI), including leading two expeditions to Botswana's Okavango Delta for the ATI series Untamed!.

After college, Anderson worked for the Montana Department of Fish, Wildlife and Parks as a wildlife rehabilitation technician, and for several privately owned wildlife parks as an animal keeper and trainer. In 2002, he adopted an orphaned grizzly bear cub, Brutus, from an overcrowded wildlife park named Yellowstone Bear World where the cub was destined to spend his life in the park; now the bear lives in a sanctuary Anderson built just for him near Anderson's home. This led to Anderson's Future career as trainer to Brutus and co-owner of Montana Grizzly Encounter.

Anderson is the founder, Director and co-owner of Montana Grizzly Encounter Rescue and Educational Sanctuary in Bozeman, Montana. Anderson founded the sanctuary in 2004 as a place to raise Brutus, rehabilitate grizzlies rescued from bad captivity situations, and aid in the study of grizzlies. Brutus lives at the sanctuary, along with several other grizzlies.

In 2006, Anderson starred along with his bear Brutus in "Expedition Grizzly," an episode of the documentary series Wild for National Geographic Channel. The episode, for which Anderson was also associate Producer, focused on his relationship with Brutus and a year-long project they undertook to observe and understand the habits of wild grizzly bears living in Yellowstone National Park. He subsequently became the regular host and Producer for the long-running wildlife documentary series Expedition Wild, which has covered many different animals including mountain lions, wolves, wolverines, and several species of bears. Some episodes have also focused on the wildlife of particular areas such as Yellowstone and the Grand Canyon. Originally airing on the National Geographic Channel and later on its sister station Nat Geo WILD, Expedition Wild has been widely syndicated, including on ABC as part of Litton's Weekend Adventure, on The CW, and online via Hulu.

Anderson was previously married to Actress Missi Pyle from 2008 to 2011. They met in 2007 during the making of the film Pretty Ugly People (2008), in which Pyle starred, Brutus had a small role, and Anderson worked as animal trainer. Brutus the Bear was best man at their wedding, which was held in September 2008 at Holland Lake Lodge in Montana where the couple had met. In 2013, Pyle confirmed in an interview that the couple had broken up.

Anderson frequently appears as himself on reality television shows, particularly those involving nature and animals. He was a featured survival expert on the Discovery Channel reality show Dude, You're Screwed, and guest starred (with his then-wife Missi Pyle) on a 2010 episode of Dog Whisperer with Cesar Millan on the Nat Geo Channel. He has been a recurring guest on talk shows including Late Night with Conan O'Brien, Conan, Fox & Friends, and Good Morning America, presenting a variety of animals including bears, baby coyotes, a wolf, a bobcat and a Eurasian eagle-owl.

In 2013, Anderson appeared on two episodes of the reality show Ke$ha: My Crazy Beautiful Life as "Casey", a "bearman" who was Kesha's possible new romantic interest. The second episode ended with the couple deciding not to pursue a relationship.

Anderson was formerly an executive Producer and host at Grizzly Creek Films, the production company that was responsible for creating the series Expedition Wild and America the Wild. As of July 2015, Anderson is currently an executive Producer and part owner of VisionHawk Films, a new Montana-based film production company specializing in epic Natural World History filmmaking.

Anderson married Stephanie Gazda in August 2016. The couple live together in Paradise Valley, Montana with their dogs Jack and Muppet, and their cats Mao and Magpie.