The movie Contact (based on his book) shaped my childhood in big ways. I must have watched it every year growing up, and I was always reading up on SETI news. I wanted to be Ellie Arroway. I finally read the book when I was about 16 and loved it even more.
I’m not old enough to have watched his Cosmos, but I’ve been watching the Neil Degrasse Tyson reboot religiously (ha). Sagan is a pretty big hero of mine, I’d have to say.