He was a star once; can he be again?

“Dickie Roberts: Former Child Star” is full of sass and sentiment, managing to be both raunchy and sweet-natured. It fits David Spade like a glove, as well it should since he and fellow “Saturday Night Live” alumnus Fred Wolf wrote the script. With Sam Weisman’s sharp-edged direction, this sleek and sunny comedy is an all-too-rare example of smart and inventive Hollywood filmmaking.

Roberts is only 35 but a has-been, once a top TV child star now parking cars at Morton’s. Still, the irrepressible Dickie dreams of a big comeback and believes that Rob Reiner’s next movie, which has to do with a man discovering heaven in his own backyard, is the perfect vehicle for him. Dickie actually wangles an interview with Reiner, who tells him he in fact would be good for the part if only he were “a real person.”

Final casting is three months off, and because Dickie has just received a $30,000 advance for his tell-all memoirs, he decides to use the money to pay a family to take him in for about a month so that he may recapture his lost childhood and thereby become a more normal person.

George Finney (Craig Bierko), a used-car dealer, takes him up on the offer. Dickie shows up at the Finney’s handsome, spacious Colonial in an upscale, older neighborhood to be met by an understandably dumbfounded Grace Finney (Mary McCormack), who had no knowledge of her husband’s agreement, and her equally perplexed young son, Sam (Scott Terra), and little daughter, Sally (Jenna Boyd).

Dickie is a piece of work, and the Finneys, if they’re to follow through, face a real challenge. Dickie is fast-witted and outrageous, totally uninhibited and with virtually no familiarity with the concept of appropriate behavior. He does not know who his father is, and his mother (Doris Roberts) abandoned him when his series was canceled. There’s not much inner man, let alone boy, in Dickie, and Spade conveys this without resorting to shameless heart-tugging.

The interplay between Dickie and his temporary family is inspired, the source of zany humor as well as real pathos. Spade and his colleagues are not afraid of showing emotion, but they also know just when to cut loose and remind their audience that it’s watching a barrel-ahead comedy. The filmmakers know that the ultimate consequences of Dickie’s big moment of truth are highly improbable, so they distract viewers with a fast and funny epilogue that culminates in a surprising and exuberant credit sequence.

Spade could not ask more from his supporting players, who include Jon Lovitz as Dickie’s agent, loyal far beyond the call of duty, and Alyssa Milano as his far-from-loyal girlfriend. There’s also a scene with a host of real-life, former child stars playing Dickie’s pals and poker buddies that’s amusing and affectionate.

*

‘Dickie Roberts: Former Child Star’

MPAA rating: PG-13, for crude and sex-related humor, language and drug references

Times guidelines: Some of the film’s humor may be too risque for some families.

David Spade...Dickie Roberts

Mary McCormack...Grace Finney

Craig Bierko...George Finney

Scott Terra...Sam Finney

Jenna Boyd...Sally Finney

Jon Lovitz...Sidney Wernick

Alyssa Milano...Cyndi

Rob Reiner...Himself

Paramount Pictures presents a Happy Madison production. Director Sam Weisman. Producers Adam Sandler & Jack Giarraputo. Executive producer Fred Wolf. Screenplay Wolf & David Spade. Cinematographer Thomas Ackerman. Editor Roger Bondelli. Music Christophe Beck and Waddy Wachtel. Costumes Lisa Jensen. Production designer Dina Lipton. Art director Marc Dabe. Set decorator K.C. Fox. Running time: 1 hour, 39 minutes.

In general release.