Been a while since I'd done this, but I remember back in, like, 2009 I watched Speed Racer (in this case, the 2008 movie) and got sooo fixated on it that I decided to binge the lead actor's, Emile Hirsch's, entire filmography. I don't think I got too far, however - I've watched The Girl Next Door, Alpha Dog and Kings of Dogtown for sure, maaaaybe The Dangerous Lives of Altar Boys (don't quite remember!) and started Into The Wild - can't quite remember if I finished it. All of which were not the kind of movies I'd watch naturally and some of them were an experience to watch as a little teen (especially The Girl Next Door, which is like, about adult film industry if I remember correctly, albeit mixed with romantic comedy), so yeah, definitely an interesting thing to do :D
I think I also tried doing a similar thing with Melanie Scrofano in, like, 2020 or 2021, after watching Wynonna Earp. Didn't get too far either. Mostly 'cause I wanted to focus on things where she was in the lead (or one of them at least), and preferably movies, not long series, and there wasn't too much of that. But I got to see Mangiacake, which is, I assume, much funnier if you're Italian, and short films Unidentified Woman and Break In, which I liked. Almost convinced myself to see Ready or Not for her, but soooo not my thing so I still haven't managed :p Still haven't watched her short from 2023 by the way. I should remedy that.
So in short, I never really picked an actor and watched everything, but I definitely had moments of "I loved this actor in [this], but I ran out of [this], so I shall watch everything with them I can get my hands on instead".