There are rules about how much young actors are allowed to work. They ought to apply to old actors, too, because the load Harrison Ford is carrying on the new Apple TV+ series “Shrinking” should be against the law.

The 80-year-old Ford plays one of the three central characters in the half-hour therapy dramedy (theramedy?), which premieres with two episodes on Friday, and nearly every moment I enjoyed revolved around him. (Nine of 10 episodes were available for review.) He plays Paul, the senior member of a psychotherapeutic practice, an old-school boss with a sharp tongue and a well-hidden soft heart.

An actor of Ford’s seniority could be excused if he coasted through the part or tried for a crowd-pleasing twinkly grouchiness. But Ford is made of tougher stuff; except for a few aw-shucks grins, he never panders. Instead of riding on top of the role, he relaxes into it and makes Paul smart, funny and sexy — it’s no wonder that his junior partners Jimmy and Gabby, played by Jason Segel and Jessica Williams, idolize him. (He’s Jimmy’s father figure and Gabby’s hot uncle.)

Ford maintains his, and Paul’s, quiet authority whether singing along in the car to Sugar Ray or negotiating that most dangerous of scenes: the party at which the older authority figure accidentally gets high. When Paul, who’s in the early stages of Parkinson’s, sweet-talks his sexy neurologist into a road trip, he tells himself — with just a hint of surprise — “You’ve still got it, man.” The same goes for Ford.

It’s tempting to just keep talking about Harrison Ford, because aside from Paul, the news about “Shrinking” isn’t so good. Segel created the show with Bill Lawrence and Brett Goldstein from the “Ted Lasso” team, and it’s focused on his character, Jimmy, another in the long 21st-century line of grieving man-children. Jimmy’s wife has died, and he has been neglecting his teenage daughter, Alice (Lukita Maxwell), who’s essentially being raised by their next-door neighbor Liz (Christa Miller). The show begins with Liz’s being woken up yet again by the noise from Jimmy’s grief-fueled late-night carousing.

The through line of the show is, of course, Jimmy’s growing up and redeeming himself, and the subplots work in parallel to that: Gabby has to deal with the fact that her marriage is breaking up, and the workaholic, emotionally unavailable Paul has to repair his relationship with his daughter. On paper, it’s pretty heavy going.

But the creators — especially Lawrence — are sitcom guys, and structurally, “Shrinking” works like a sitcom. It alternates a limited number of comic setups, often involving unfortunate encounters or Jimmy’s increasingly harebrained approach to therapy. (Fed up with his seemingly unfixable patients, he becomes a “psychological vigilante,” ordering one to leave her husband and spying on another’s dates.) The cycle of yelling, crying and apologizing is so constant that even within episodes you lose track of what people are yelling about and what they’re apologizing for.

Tonally, however, the show is a quiet, somewhat monochrome drama, and the result is that it never quite feels in sync. The machinations and emotional excesses of the plot are meant to be laughed off and forgotten, sitcom-style. But without the stylization and exaggeration of the traditional sitcom — like, say, “Scrubs” — they’re jarring and sometimes uncomfortable. When Jimmy’s patient Sean (Luke Tennie), a veteran with post-traumatic stress who gets arrested for savagely beating someone up, moves in with Jimmy and the 17-year-old Alice, the all-around inappropriateness of the situation is turned into a running joke that isn’t as easy to gloss over as the show thinks it is.

The light-heavy, manic-melancholy, satiric-sincere straddle that “Shrinking” is trying to achieve is a difficult one to pull off; the shows that get the most praise for doing it tend to be blandly inoffensive, like “Abbott Elementary.” But the real problem with “Shrinking” may be simply a paucity of ideas. The idea that the only way to deal with grief is to face it and come out the other side, as one of the characters helpfully explains, isn’t a lot of fuel for a farcical comedy.

The toll of that thinness in the conceptualization and writing falls on the talented cast. Jimmy seesaws between angry grief and middle-class-white-dad dorkiness (the debauchery evaporates after the opening minutes), and Segel isn’t able to make anything distinctive of the character. Williams fares better as Gabby, milking some laughs from her brashness and sexual candor, and Maxwell is touching as the perpetually confused Alice. But the female characters are generally pretty one-note. The wonderful Lily Rabe has little to play as Paul’s bitter daughter, and the script is especially unfair to Miller’s Liz — we’re supposed to think that her caring for Alice is as much about her neediness as it is about her compassion, a notion that rings totally false.

The humor lies largely in sitcom-style repartee and ripostes that, in the show’s context, are muffled and tend to land too softly or flatly; only Ford and, to a lesser extent, Williams consistently make them work.

The flattest element of the writing, by far, is the frequent put-downs (often self-inflicted) of the white characters, which the writers apparently feel are so self-justifying that they don’t bother shaping them — whiteness is simply pointed out, and everyone pauses for the laugh. As an attempt to even the score when it comes to ethnic humor, I have no problem with it, but you could at least take the trouble to write actual jokes.