Iain Armitage's Height Transformation Has Caught Fans' Attention
Fans witnessed "Young Sheldon" star Iain Armitage's transformation as he grew up over the duration of the series, which eventually led to a lot of chatter about his growth spurt. When the show's first season premiered in September 2017, Sheldon Cooper's character was 9 years old. Armitage was a great match to play the childhood version of "The Big Bang Theory" character, as he was the same age at the time. While Season 1 was airing, Armitage took to X, formerly Twitter, to share a pic of himself with his TV siblings, Montana Jordan and Raegan Revord, standing in front of a growth chart. The snap was posted in April 2018, and the series star appeared to be a diminutive 4 feet, 4 inches.
As the series progressed, so did Armitage's notches on the growth chart. When the final season of "Young Sheldon" started airing in February 2024, Sheldon's character was 14 years old. Obviously, both the character and the actor portraying him would have grown significantly since the early seasons. Armitage, 16 years old at the time, had gone from a child to a young man. Viewers noted that Armitage playing a young Jim Parsons — the actor who originally played Sheldon on "The Big Bang Theory" — was a perfect choice to fill the actor's shoes. "Sheldon grew so tall especially in the last seasons [...] it really lines up with how tall he is in 'TBBT,'" a fan wrote in a Reddit post around the time the final episodes aired. Armitage is listed as standing 5 feet, 10 inches tall, which is just a few inches shorter than Parsons' 6-feet, 1-inch build.
Fans swooned over Iain Armitage's grown up pics
In April 2024, as the final season of "Young Sheldon" aired, Iain Armitage posted to Instagram. The picture was a behind-the-scenes throwback shot of his 8-year-old self filming the series' first episode. "I don't think this kid could have anticipated what it would feel like to film our final scene all these years later," the actor wrote in the touching caption alongside a snap of young Armitage holding a briefcase at school.
The following year, fans could see just how much Armitage had grown since the series' early days. Not long after turning 17 years old, the "Young Sheldon" alum uploaded two selfies to Instagram in which he wore glasses and struck Blue Steel-type poses that gave him a mature air. Followers popped up in the replies to comment on how much Armitage had changed. "You're growing up too fast [Kleenex emoji] just the other day you went to school in a bow tie," one wrote. "Gosh, I almost didn't recognize him. He's quite handsome," another user commented about the glow-up.
Armitage's transformation continued after "Young Sheldon" ended, as he returned to CBS for a guest appearance on "Ghosts" in April 2026. Afterward, Armitage spoke about how he looked forward to trying other roles different from Sheldon Cooper. "Because I started doing this when I was so young, I have a lot of people that will come to me and tell me, 'You look so different,'" he told Us Weekly. Armitage did mention that while he was happy to move on as he aged out of the role, he still embraced fans knowing him as Young Sheldon.