Today, critics are saying the risk was worth it, reports CBS News correspondent Richard Roth from London.
Says Quentin Lett, critic for The Daily Mail, "This, if you like, is Harry Potter in the raw. In the physical sense but much much more than that, it's in the raw psychological and he gives a tidy performance. "
Writes Michael Billington in The Guardian: "Forget all the prurient press speculation about Harry Potter's private parts," referring to a scene at the end where Radcliffe is nude. "The revelation in this revival is that Daniel Radcliffe really can act."
Even before Tuesday's opening night at the Gielgud Theatre, the Internet was awash with anticipation and outrage. In the play, Radcliffe strips naked. He simulates sex. He smokes.
Radcliffe, 17, said taking on the role of Alan Strang, a disturbed young man whose obsession drives him to blind horses with a metal spike, "was a risk but it was an exciting one. But if you never took a risk it would just be diabolical and boring all the time."
Although the play, with its nudity, has been controversial for decades, Radcliffe said, "The nudity for me was just something that came with the character, it wasn't something that attracted me to the part or repelled me, it was just a thing."
He added that he took the role partly from a desire "to shake up people's perception of me."
On those grounds, the play was a success before it opened. Hundreds of Potter fans have swarmed the theater during previews. Canny marketing — including carefully cropped publicity photos of Radcliffe's naked torso — has helped the production sell $3.1 million worth of tickets in advance. Ticket prices range from about $100 to $38.
But not everyone is happy.
The anti-smoking group ASH said Radcliffe's onstage cigarette was "regrettable." The group said it feared Radcliffe's status as a role model might encourage young people to start smoking. Warner Bros., the studio behind the Harry Potter movies, issued a statement denying reports that it was unhappy with Radcliffe's edgy new image. The studio said it considered Radcliffe a "great collaborator" and supported the "artistic choices he makes as an actor."
Radcliffe said he saw the stage nudity that comes with the role as "a rite of passage."
"That iconic scene is the physical and emotional climax of the play," he was quoted as saying by The Daily Telegraph newspaper. "So if I do that with pants on, it would be crap."
He said he took the part in a bid to move beyond Harry and assert his acting credentials. "With this, they can say I'm good or terrible, but the one thing they can't say is I haven't challenged myself."
"Equus" opened in 1973 at London's National Theatre, before a successful run on Broadway starring Anthony Hopkins. Richard Burton and Peter Firth starred in a 1977 film version.
The new production co-stars Richard Griffiths — Harry's dastardly Uncle Vernon in the Potter movies and a Tony Award winner last year for "The History Boys" — as a psychiatrist who interviews the troubled youth.
This nudity doesn't seem to have put off his Harry Potter fans. "I thought he was a bit hot before...as well, " one young woman told CBS, laughing. "Yeah, yeah, he's cool." A young French fan said, " I think its nice for him. He can't stay Harry Potter forever."
But Radcliffe will have to remain as Harry Potter for a while longer. He returns as the teenage wizard in "Harry Potter and the Order of the Phoenix," slated for release July 13. The sixth Potter film, "Harry Potter and the Half-Blood Prince," is due to start filming this summer, after the run of "Equus" ends in June.