As a local politician struggles with his microphone during the dedication speech, the "wacky, fun-loving" Monkees (Micky Dolenz, Davy Jones, Peter Tork, and Michael Nesmith), suddenly interrupt the ceremony by running through the assembled officials, to the sound of various horns and sirens.

But no matter what they try—deliberately flubbing their lines in scenes from their TV show, pointing out to other characters that they're really just actors making a movie, complaining to producers Jack Nicholson and Bob Rafelson who are on the set but not part of the film, smashing through the painted paper walls, walking off the set and into the street, physically attacking other actors for no reason, and making everyone they encounter mad at them—they discover that their every word and deed was predetermined to the finest detail by the script of the movie they're in and the director directing it.

The plot and peak moments of the film came together at an Ojai, California, resort where the Monkees, Rafelson, and Nicholson brainstormed into a tape recorder,[3] reportedly with the aid of a quantity of marijuana.

[4] When the band learned that they would not be allowed to direct themselves or to receive screenwriting credit, Dolenz, Jones, and Nesmith staged a one-day walkout, leaving Tork the only Monkee on the set the first day.

Bright color filters heighten the visual effect and dreamlike touch of the passages, which include mermaids rescuing member Micky Dolenz in the film's start.

Andrew Sandoval, author of The Monkees: The Day-By-Day Story of the 60s TV Pop Sensation, commented that, "It has some of their best songs on it and ...the movie's musical performances are some of the most cohesive moments in the film.

The music of the film takes the darkness and occasional satirical elements of the Monkees' earlier tunes and makes it far more overt, as in "Ditty Diego" or "Daddy's Song", which has Jones singing an upbeat, Broadway-style number about a boy abandoned by his father.

The soundtrack includes: Trailers summarized it as a "most extraordinary Horror, adventure, western, comedy, love story, mystery, drama, musical, documentary satire ever made (And that's putting it mildly)."

Rafelson commented that he and Nicholson were arrested at the New York City premiere on October 6 for trying to put a sticker on a police officer's helmet as he mounted his horse.

[6] A poor audience response at an August 1968 screening in Los Angeles forced the producers to edit the picture from its original 110-minute length.

[6] This ad was a parody of Andy Warhol's 1964 film Blow Job,[citation needed] which only showed a close-up of a man's face for an extended period, supposedly receiving 'head'.

Receiving mixed critical reviews and virtually non-existent box office receipts, the film succeeded in alienating the band's teenage fanbase while failing to attract the more adult audience for which they had strived.

Going through ersatz Beatle songs, and jokes and motions, their complete lack of distinction of any kind ... makes their performance modest and almost brave.

"[6] Daily Variety was also harsh, stating that "Head is an extension of the ridiculous nonsense served up on the Screen Gems vid series that manufactured the Monkees and lasted two full seasons following the same format and, ostensibly, appealing to the same kind of audience."

But the review applauded Rafelson and Nicholson, saying that they "were wise not to attempt a firm storyline as the Monkees have established themselves in the art of the non sequitur and outrageous action.

In Straight Outta Cullompton, author Adam Foley wrote more glowingly, "Julian [Hewings]: 'I was watching Head, The Monkees film, and there's a bit at the beginning when Micky Dolenz falls from Golden Gate Bridge and he's got a pair of slightly flared boot cut jean cords on with a pair of (Adidas) Gazelles, probably the first ones that ever came out and this stripy t-shirt and I thought "Wow, that's what I remember when I was a kid – that's what everyone used to wear when they went to school."

The NorthEast ComicCon & Collectibles Extravaganza hosted a 50th anniversary screening of the film at the Regent Theatre (Arlington, Massachusetts), on July 6, 2018.

A portion of that screening benefited the Cystic Dreams Fund a 501(c)(3) non-profit organization and Dolenz conducted a lengthy question and answer before introducing the film.