Fully Committed Ryan Palmer as Sam 3.jpg

Ryan Palmer plays nearly 40 characters in “Fully Committed,” running through July 4 at The Theater Barn in New Lebanon, N.Y.

NEW LEBANON, N.Y. — Sam Callahan, the struggling young actor at the center of Becky Mode’s sly comedy “Fully Committed,” is not having a very good day. His boyfriend has not only moved out of their apartment, but also Sam’s life.

Increasingly concerned that his acting career is on the verge of tanking, Sam is anxiously waiting to hear from his agent regarding callback auditions for a role in a major production at Lincoln Center. He also is hoping against hope that he will be able to get Christmas Eve and Christmas Day off from his job, as a reservations clerk at New York’s hottest restaurant, to spend time with his father and siblings for their first holiday together since the recent death of their mother.

And that’s only the beginning as Sam — played resourcefully by a likable Ryan Palmer in director Sky Vogel’s season-opening production at The Theater Barn — reports for his shift. It turns out, he will be on his own to face the tsunamilike onslaught of reservation requests, inquiries and demands from a seemingly unending array of fussy, picky “entitled” guests.

One coworker has called in sick. She’s been diagnosed with lupus. The reservations manager, Bob, calls in to tell Sam his car has broken down on the Long Island Expressway and he’s waiting for a tow. The truth, it turns out, is that he’s at a job interview at a major retail chain.

It’s not only the demands from without that overwhelm Sam. He is at the beck and call of the restaurant’s owner, maitre d’, executive chef, hostess. Nothing on this day drives Sam as low and down as being forced by the upper echelons of management to clean up, literally, the mess created in the men’s room when a customer loses control of his bowels.

It’s a shameful humiliation for anyone, especially someone who, as played by Palmer, is a guileless, decent, very-good-at-his-job, stand-up guy who wants nothing more than to do what he loves best — act, and share his life with a loving partner.

It should come as little surprise that by the time “Fully Committed” has run its intermissionless 90 or so minutes, Sam not only has learned the rules of the game, but also how to apply them on his own behalf.

“Fully Committed” has only one actor, but it calls upon that actor to play roughly 40 sharply defined characters. Palmer moves creatively and adeptly from one character to another to another and back again.

Mode has little patience with hypocrisy; the pretenses people wear as if they were showing off prized pieces of jewelry. She also is keenly tuned to the power plays, the assertions of authority and privilege within the pecking order of the restaurant’s upstairs-downstairs culture, which finds the reservation clerks at the bottom of the chain — figuratively and especially literally. Their office is in the restaurant’s cluttered basement, cleverly designed by Sam Slack.

“Fully Committed” is the first offering in the first Theater Barn season under the supervision of its new artistic and administrative team, led by producing artistic director Allen Phelps, who has taken over from his 83-year-old parents, Joan and Abe Phelps. The couple, who now serve only as theater board members, founded the non-Equity Theater Barn in 1984. Their 54-year-old son is joined by associate producer Jon Earle and associate artistic director Monica Bliss.

An encouraging start.