Shortly after university, Henning was awarded a Canada Council for the Arts grant. The terms of the grant required Henning to study magic. He did so, traveling to view first hand the talents of such magic greats as Slydini and Dai Vernon. Doug studied under Tony Slydini and considered him his primary teacher of magic.
With the intention of returning magic to its “glory days”, Henning worked to perfect his craft. Garnering financial support, he developed a live theatrical show,Spellbound, directed by Ivan Reitman, with music by Howard Shore and co-starring actress Jennifer Dale, a musical that combined a dramatic story and Henning's magic tricks. The show opened in Toronto, where it broke box office records. Henning reworked the show after catching the attention of New York producers, and took it to Broadway as The Magic Show, with songs composed by Stephen Schwartz. Debuting in 1974, the show ran for four and a half years, and earned Henning a Tony Award nomination.
Following his Broadway success, Henning approached NBC with the idea of producing a television special. It wasn't until Henning suggested that he would reproduce live Harry Houdini's famous and highly dangerous water torture escape — for the first time since Houdini performed it himself — that the NBC executives signed him.
Henning spent the next eight months reworking his stage act for TV and practicing the water torture escape act. More than 50 million viewers tuned in for the December 1975 broadcast of Doug Henning's World of Magic, hosted by Bill Cosby. Henning successfully performed the water torture illusion, although he did not break Houdini's time record. The event was the first of seven annual broadcasts,which would eventually bring Henning seven Emmy Award nominations, including two back-to-back in 1976 and 1977 for World Of Magic.
At the end of each World of Magic performance, Henning addressed the audience with the same monologue: "Anything the mind can conceive is possible. Nothing is impossible. All you have to do is look within, and you can realize your fondest dreams. I would like to wish each one of you all of life's wonders and a joyful age of enlightenment."
In 1977, Henning co-wrote a biography of Houdini, Houdini: His Legend and His Magic. He created illusions for an Earth, Wind and Fire tour in 1979, and for two of singer Michael Jackson's concerts, including his 1984 Victory Tour.citation needed] There were a total of six Wonder Whim characters. Each came with an animal friend, a personalized story, and a magic kaleidoscope wand of colors and patterns.