This guy loved Lady Catelyn forever, but he couldn't protect her from the betrayal of Roose Bolton. Since her death, Baelish has turned his attention to her daughter Sansa, who bears a striking resemblance to her mother.
According to Aidan Gillen, who has portrayed Littlefinger since Season 1, his desires have evolved past an obsession and into an opportunity. During an interview with The New York Times, the actor talks about Littlefinger's current motives.
"There’s always something more to it when it involves the Starks, given his history with Catelyn Stark and that rejection, and that that’s what’s driving him," Gillen revealed. "But I wouldn’t say the undermining of the Stark family has been a goal. It’s opportunistic. He couldn’t have foretold that Arya was going to show up again, and that Bran was going to show up again. He has played his part in the rise of the Starks, showing up last season with the Knights of the Vale, but he will also undermine it and exploit it. That’s what he’s doing — he’s trying to drive wedges between all of them."
As bad as that sounds, Gillen persists that Littlefinger isn't as bad as he seems. The actor stated that his character didn't set out to be a villain.
"It's a reaction to being humiliated and spurned as a young man in matters of love. And he's good at it, you know? This Game of Thrones universe, it's a wicked world."