Douglas James Henning was born in the Fort Garry district of Winnipeg, Manitoba, on May 3, 1947. At age six, he became hooked on magic when he saw Richiardi Jr. on the Ed Sullivan Show performing a levitation act. He then began practicing magic tricks himself and gave his first paid show at age 14, during a friend's birthday party. In 1961, he placed an ad in the local newspaper and quickly performed two to three shows a week for $15 each. He quickly became popular and at age 16, he was invited to perform magic on local television shows. Around this time he also began attending the magic meetings of the Hat & Rabbit Club of Toronto, the famous Abbott's Get-Together in Michigan, and the conventions of the Houdini Club of Wisconsin.

After completing high school, he studied psychology at McMaster University in Hamilton, Ontario, in preparation for a career in medicine. It was there that he met Ivan Reitman, who was the director of the school's theater production in 1968. In order to support himself, Henning worked at the international airport of Toronto as a baggage handling worker. A grueling job that will lead him to create a partnership with his girlfriend at the time, Mars Barrick, and to create magic in the region's bars and nightclubs. After obtaining his degree in science and psychology, Henning decided to take a year off before entering medical school to continue performing magic. The duo Henning and Mars support the best artists in the country and travel from coast to coast.

Henning soon realizes that he needs to perfect his theatrical style and certain aspects of his magic. Luckily, he obtained a $4,000 scholarship from the Canadian government to study his art after convincing a panel of several officials that magic, combined with theater, is an art to be discovered and explored. After obtaining his scholarship, he studied mime under Adrian Pecknold (1920-1999) and dance with a Canadian choreographer. It also gives him the opportunity to meet and study with eminent magicians such as Tony Slydini and Dai Vernon and observe their masterful techniques up close.

In the 1970s, he developed a theatrical show, Spellbound, written by David Cronenberg and directed by his friend Ivan Reitman, with music by Howard Shore. Presented at the Royal Alexandra Theater in Toronto, the show, which combines magic, music and a dramatic storyline, was a huge success and broke box office records. He then reworked the show and found himself on Broadway in 1974 with The Magic Show.

Henning's success on Broadway prompted the NBC network to offer him a magic special, broadcast live on television, on December 26, 1975. In front of more than 50 million viewers, Henning succeeded in presenting the illusion of the Chinese Torture Cell by Houdini. Chained and locked underwater in a steel cage, he frees himself in less than a minute and emerges smiling to thunderous applause. The show made him an international celebrity overnight. NBC will roll out the red carpet for 7 other television specials.

Henning possessed incredible manual dexterity and superior showmanship. He was an expert in several areas of magic, including stage illusions, close-up tricks, and escapes. Additionally, he is credited with single-handedly reviving public support and interest in magic after a very long slump. He achieved this by combining magic with flamboyant costumes, comedy and music to make it appealing to a new generation. A charismatic personality, he always radiated enthusiasm, traits that endeared him to the public. In 1983, he produced and starred in the Broadway musical Merlin and, the following year, began a new, more intimate show entitled Doug Henning and His World of Magic. In 1986, he became a consultant for the Disney organization and created “wonder workshops” for the “Imagineers” team and convinced them to add more magic to their park. He also helped design the Kingdom Island theme park in Washington, DC.

In 1987, he suddenly abandoned magic and announced his intention to promote the transcendental meditation movement that he had heard about while touring India. In 1992, he announced that he and the movement's spiritual teacher and founder, Maharishi Mahesh Yogi, would build a $1.5 billion theme park near Niagara Falls, Ontario.

Henning made two unsuccessful attempts for political office in Canada in 1990 and 1992 as a member of the National Law Party. In 1999, Henning was still actively involved in the planning of the Niagara Falls Park and an eventual return to magic when he was diagnosed with liver cancer. He died five months later at Cedars Sinai Medical Center in Los Angeles. He was only 52 years old. His ashes were scattered in the Pacific Ocean off the coast of Redondo Beach, California.