I'm sure there's a simple solution for this:

[squareking]

I need to tell a certain .exe to run when I launch a game (from Steam). If it could see when the game stops and shut itself off as well, that'd be doubly swell. Any ideas?

[somini]

I need to tell a certain .exe to run when I launch a game (from Steam). If it could see when the game stops and shut itself off as well, that'd be doubly swell. Any ideas?

You can make a batch file to run the exe you want, then the game (use "steam://run/{AppId}).
Then, convert that file to an exe using this for example and adding that EXE as a non-steam game.
It might just work. It's not THAT simple.

[tenseiga]

^ what he said, also add the .bat file to the steam library with the option to add a non steam game on the steam client. thats the best i can think of.