I just steal ‘em. Do you need an editor for a big city newspaper? There’s the history’s for Perry White and J.J.J. on their comic company’s websites. Not realistic enough? Look up Ben Bradley on Wikipedia, he was the editor of the Washington Post during Watergate.
Do you need a soldier or a cop? Comics, movies, TV and history are full of them. I like to use obscure stuff and go whole hog. I saw a bad movie that starred Tommy Lee Jones as the Commander of a squadron of Apache helicopters. (Fire Birds) Soon after my Star Wars campaign had a new Commander for its B-wing squadron.
Check out the episode of Big Bang Theory where Wolowitz is the DM for their D&D game. The actor is a very good mimic and breaks out celebrity voices for all the NPC’s. You don’t have to go that far, but I find that casting a real person in the role gives me an immediate grasp of what they sound, look and behave like.
Good luck.