If this story began with a narrator, it would go something like this: Seven years ago,

just a few weeks from making his debut as the face of “Young Sheldon,”

the prequel to CBS’s blockbuster comedy “The Big Bang Theory,”

Iain Armitage was a spirited, baby-faced 9-year-old dangling upside

down on a pair of gymnastic rings at a park in Studio City during a break from his very grown-up gig.

That’s how this reporter first met Armitage. He was a kid who skipped and hopped

across the park pavement and carefully set up a deck of cards to finesse a magic trick.

But even at this tender age, he already had a list of credits that included HBO’s “Big Little Lies,” where he played the son of Jane Chapman (Shailene Woodley) who sets off some mommy tension after he’s accused of bullying a classmate, as well as the Brie Larson-led family drama “The Glass Castle” (2017) and the Netflix movie “Our Souls at Night” (2017).

But Armitage’s career-making turn in “Young Sheldon,” the coming-of-age sitcom focused on the childhood of Sheldon Cooper, the egotistical and socially awkward theoretical physicist memorably portrayed by Jim Parsons in “Big Bang Theory,” is coming to a close. The series premiered in fall 2017, becoming the No. 1 new comedy that season, and remained one of the network’s strong performers throughout its run. It even spawned a spin-off, “George & Mandy’s First Marriage,” which will launch this fall. (The series centers on Sheldon’s brother, George Cooper Jr., a.k.a. Georgie (Montana Jordan) and Mandy McAllister (Emily Osment) as they build a life together in 1990s Texas.)

Now, Armitage is a couple month’s shy of his 16th birthday, his voice is deeper, and he’s swapped gymnastic rings for pilot lessons. And he’s saying goodbye to Sheldon, a character he’s played for nearly half his life, with Thursday’s series finale of “Young Sheldon.”

The final two episodes of the series, which aired back-to-back and are now available to stream on Paramount+, followed the Cooper family as they grappled with the death of their patriarch, George (Lance Barber), and prepared for his funeral; and Sheldon making the move to California to attend Caltech, where he’ll meets his “Big Bang Theory” pals Leonard, Raj and Howard.

Over a video call from New York, Armitage discussed his growth as an actor, watching Sheldon reach Caltech, and life after “Young Sheldon.” This interview has been edited and condensed for clarity.

Then and now: Iain Armitage, left, and Jim Parsons on the set of “Young Sheldon” in 2017, left, and in 2024.

“Young Sheldon” was not your first professional onscreen role, but it’s been your longest. How do you feel you’ve grown as an actor across the seven seasons?

It’s funny to think about because, especially with this show, I’ve fallen into such a rhythm with this character. I’ve been doing it for seven years, so it doesn’t really feel that much like a massive acting challenge anymore because, up until three weeks ago, I was doing it every day, for five days. I go through hair and makeup, I slip on those shoes and I’m in character. The more interesting thing, to me at least, will be when I next act. How does that look?

Does this feel like the right time for you to say goodbye to Sheldon?

Yeah. For so many people on our set, myself included, it was very hard to say goodbye. But I think it would have been hard to say goodbye if it had happened tomorrow or in 10 years. I don’t necessarily think that for me it was this massive letting go where I was so mournful it was happening right now. At the end of the day, as much as I love it, and as fun as it has been, it is a job. And all jobs like this do come to an end. I’m looking forward to what happens next.

What was the reaction like at the table read for the finale? When you got that final script, did you want to read it right away or did you put it off?

We don’t do table reads, because we’re cool. I think we did three table reads in the first season and then we stopped. Everyone was trying to kind of get the first copy of the last script just to have said, “Oh, I’ve read it. Oh, it’s really hard.” I didn’t buy into that game. I think I was one of the last people to read it, not because I was trying to put it off, but more just because I waited to get the scripts at the normal time. Reading it definitely was strange. And it did feel like an ending. But there’s going to be an incredible new spinoff with Georgie and Mandy [the characters played by Jordan and Osment, respectively]. It’s not really an ending, it’s a beginning in a way.

Fans of the original series know that a pivotal turning point in Sheldon’s life was the death of his father, George, who died of a heart attack as we see in this show. How was it to face that moment as Sheldon?

It was interesting the way it hit me because it wasn’t how I expected. I expected to be sad or kind of touched by how long we’ve gotten to know this character. But for me, it’s less about George and more about Lance. Lance is such a wonderful guy. It was more hard having him not be on set for the finale for certain scenes. We had that dinner scene without him. He brings such a light to the set … and he’s got such a big personality.

Sheldon is someone who’s very literal and matter of fact, not really likely to express emotions or know how to deal with social situations or relationships. What struck you about how he was processing his father’s death?