Lisa Schwartzbaum at Entertainment Weekly gives the film a B+ and writes about John Hawkes:

But The Sessions is first and foremost about Hawkes’ virtuoso performance, one of those My Left Foot-y transformations that make audiences verklemmt and generate awards talk. And second, it’s about the elegant matter-of-factness with which the 49-year-old Hunt bares herself, body and actorly soul, for the job. (Because it must be said: wowza.) In an extraordinary approximation of the real O’Brien, Hawkes continues to burnish his reputation as one of those rare artists who know how to disappear into a role with a modesty that cloaks the complexity of the work. And in the lovely choreography between Hawkes and Hunt, as natural-looking as it is unusual, The Sessions becomes a dance of joy in the midst of severe challenge, and a movie with a light spirit that lifts a tale of heavy fate.

Rolling Stone’s Peter Travers gives it three and a half stars:

And Hawkes (Winter’s Bone, Deadwood) does the kind of acting that awards were invented for. Having learned to twist his body, use a mouth stick to dial a phone and type, and suggest the sheer effort it took for O’Brien to simply breathe, Hawkes and his technical virtuosity are astounding. But it’s how Hawkes uses his voice and expressive eyes to reveal the inner Mark that makes his performance a triumph.

Steven Holden at the New York Times says, “At the risk of sounding hyperbolic, I would like to nominate John Hawkes and Helen Hunt in The Sessions as the movie couple of the year.”

Their extraordinary connection while re-enacting the true story of a disabled, virginal 38-year-old writer and his sexual surrogate infuses the movie, written and directed by Ben Lewin, with a piercing depth of humanity and no small amount of humor.

…From the moment Ms. Hunt appears, “The Sessions” becomes a different movie on a much higher plane. Cheryl has never worked with someone like Mark, who must remain on his back, his thin, fragile body painfully contorted. This married woman is exploring uncharted territory every bit as much as Mark, and the therapy is a dual journey in discovery. Inevitably, she makes mistakes.

…Mr. Hawkes is entirely convincing in his portrayal of a man who is by turns vulnerable, wittily self-lacerating, charming and erudite. You can feel how increasingly difficult it is for both partners to follow the rules once they have reached a certain level of intimacy.

At the Los Angeles Times, Betsy Sharkey writes, “The shocker about The Sessions, starring Helen Hunt and John Hawkes, is not the full-frontal nudity, or its provocative story of a sex surrogate who helps a 38-year-old in an iron lung lose his virginity. It’s not even the priest’s blessing allowing the out-of-wedlock sex acts.

Rather, it’s the humanistic way in which “The Sessions” deals with what sex at its best can be — emotional, spiritual, physical, pleasurable, soul-satisfying, life-affirming. In a country that embraces cinematic violence with such ease but blushingly prefers to keep sex in the shadows or under the sheets, the grown-up approach of “The Sessions” is rare.

…In “The Sessions,” O’Brien’s disability and desires are fully exposed. Hawkes’ body, twisted and still, his voice squeezed by the weak muscles, mirror, don’t mimic, O’Brien’s difficult reality. Because his character’s wry cynicism keeps things light, it makes for a memorable change from the darker roles — “Winter’s Bone” and “Martha Marcy May Marlene” most notably — that had come to define the actor.

…The challenge for Hunt is to channel Cheryl’s pragmatism about what is going to happen. Somehow she makes it possible to relax and just go with the story. Her performance is a brave one. Hunt truly does turn herself and her body into an instrument for healing. It is the best work the actress has done since her Oscar turn in 1997’s “As Good as It Gets.”