Charlize Theron and Seth Rogen in "Long Shot." (Hector Alvarez)

The name Jonathan Finer isn’t the most recognizable among the film credits for the upcoming political rom-com “Long Shot,” which features marquee-lighting monikers such as Charlize Theron and Seth Rogen. But Finer is at least known inside the Beltway as a Washington Post journalist turned State Department official under then-Secretary of State John F. Kerry, a résumé that landed him the gig of political consultant to the flick.

The movie’s plot is typically La La Land implausible: An uber-poised, model-gorgeous secretary of state, played by Theron, re-connects with a schlubby, out-of-work journalist (that would be Rogen’s character) for whom she once babysat. The pol hires the reporter to write speeches for her, and — of course — romance ensues. But Finer’s job was to inject the project with a bit of global-diplomacy realism based on his days in Foggy Bottom.

Finer, whose current gigs also include private-sector consulting, teaching at Princeton and serving as an adjunct fellow at the Council on Foreign Relations, chatted with us about Rogen’s ad-libbing, where the movie takes creative liberties and why you shouldn’t try to smuggle your stash into the State Department HQ.

So how did Hollywood come knocking?

The director of the movie, Jon Levine, went to college with [TV journalist] Alex Wagner, and I had worked with [Alex’s] husband, Sam Kass [the former chef to the Obamas who served in various food-policy roles in their administration], at the White House. So Alex put Jon and me together. They had a draft of the script, and of that initial draft, very little survived since they were reworking scenes and writing new ones. We got together in New York, and he asked if could I give feedback about what seemed realistic and what didn’t.

How did you approach your fact-checking? I mean, it obviously couldn’t be exactly realistic.

I saw the goal as being that the ridiculous things would be intentional instead of things that are very easy to get wrong. . . . Of course, I know that a secretary of state wouldn’t go on a drug-fueled bender in Paris, but I thought about what it might look like if she did.

I was trying to help them get the small things right to make the big things more credible — I think people are more likely to suspend disbelief if there’s some credibility to the details.

What kind of changes did you suggest?

One early version of the script had the secretary of state meeting with the governor of Puerto Rico, and I told them that that wouldn’t take place because the secretary of state wouldn’t meet with the leader of a territory — the secretary of state usually deals with foreign leaders.

Or they had a stage direction where she’s talking to someone from Qatar, and they are speaking Farsi — it’s Arabic there. And another thing — and this might be a spoiler here — she ends up running for president, and I suggested that she would have to resign first, because secretary of state is supposed to be a job that’s separate from politics.

What are your pet peeves about what TV and movies get wrong about Washington?

I’m not addicted to these D.C. shows — it’s just not a genre I’m super into, because I like doing other things in my spare time. I’ve never seen “Madam Secretary,” and maybe saw part of a season of “House of Cards.” When you work in that world all day, it’s more relaxing to watch something else. I read fiction and not nonfiction.

Did you spend time on set? What was it like?

I traveled to Montreal where they were filming to look at the set and to talk to costume people and the actors. I spent some time with June [Diane] Raphael, who plays the chief of staff, since that was the job I had at the State Department. I have to say that movie people understand Washington better than I understand Hollywood, but that’s a low bar.

One thing that was surprising was the humdrum aspect of filming the same scene over and over again from different angles or with slightly different dialogue. And there was a lot of ad-libbing and rewriting on the fly — I don’t know if that’s common. My sense is that it happened more than usual because Jon and Seth Rogen have a constant stream of ideas for new jokes. I really enjoyed watching that level of creativity. They’d film five ways to do a line and then decide which was best.

I have to ask: What was Charlize Theron like?

She has an aura of — there not being any doubt that she’s a movie star.

Overall, how much does the movie get right about Washington and the State Department?

I hope we got enough right that people won’t be rolling their eyes. Some things are quite realistic even amid all the ridiculousness, like the tension between the White House and State Department. And the personal toll that those jobs can take on the boss and the staff — the grueling travel schedule is well-depicted.

The sets are good. [At State,] you travel 200 days a year, so there are a bunch of scenes on the plane. I shared some pictures from my travels, and that came out incredibly realistically. And the scenes in the secretary’s office — I thought they did a good job of those re-creations.

Any plans to make movie-consulting a side hustle?

My usefulness is probably limited, but I had fun doing it. I’d certainly do it again; I just don’t know how many movies there would be in this particular vein.

Will Washington audiences like it? I mean, I think a lot of people here are pretty serious and might not admit to liking a Seth Rogen comedy …

Well, the part of Washington I like can laugh at itself. I suspect it will actually go over well. It’s not disrespectful of the people who hold these jobs or the institutions of government. It’s just pointing out some stranger and amusing aspects of them.

Okay, but could you really get into State Department headquarters [as — spoiler alert! — Rogen’s character does] with a whole bunch of drugs?

Yeah, that would be a challenge.