Here's Everything 'This Is Us' Fans Know About Kate's Teenage Boyfriend

This Is Us Season 4 Episode 4, "Flip A Coin," introduced a brand new character in a season that's been full of introductions. Usually, this wouldn't be all that notable, except for one thing: The character introduced in a love interest for Kate Pearson, from back when she was a teenager. Considering the show has always been on about how Kate can't find a date, this seems like an odd outlier. Fans are perplexed and wondering who Mark is on This Is Us. Why hasn't this come up before? Warning: Spoilers for This is Us Season 4 follow.

Viewers always knew Kate's post-high school plans were derailed with her father's death. Moreover, Kevin's choice to go to New York while Randall went to Carnegie Mellon was well established. But there's knowing it on paper, and then actually seeing Kate, stuck at home, watching endless episodes of Buffy The Vampire Slayer, while the world is turning without her.

That's why it felt heartening when a trip to the record store landed Kate a job. It's not great, but it's something that gets her out of the house. And the guy who offered it to her was pretty cute, and clearly taken with her. One would call it a step in the right direction.

But things seem to be moving pretty fast at the record store. When Episode 5, "Storybook Love," begins, Kate and her new coworker, Mark, are making out in the backroom. It's a fun fling, but Kate doesn't seem to be ready for it to be much else. Moreover, commitment is something she's not looking for, especially having seen her twin brother dive headlong into marriage without so much as a "Hey Kate, guess what?"

But there's a thing about the Pearson family, and it's what they call the "grand gesture." It's something passed down from Jack to all those in the family. (It's even passed down to Jack Jr., as fans saw in the Season 4 premiere.) It looks like Mark might be a Grand Gesture-maker as well.

Kate didn't invite Mark to the family dinner. But he listened when she said both her brothers were bringing their new significant others, and he decided she shouldn't be the fifth wheel. So he took it upon himself to find where she lived and even picked daisies to give to her for a bouquet.

But even so, fans aren't so sure about this new arrival. Whatever else has happened in the interim between 1998 and 2019, Sophie remained solid parts of Kevin's life. They may have divorced, but she's not considered a part of his life he's trying to forget.

Mark, on the other hand, was memory-holed, hard. When Kate found a picture of him in the piano bench, it caused both her and her mother to sit down. When a blast from the past can take you out like that, it's a pretty good sign that something went down. Something they decided was worth leaving behind.

Exactly what that was remains to be seen. But whoever Mark is, it looks like fans' best hope might be that this memory stays in the past.