"Who's your Daddy?"
"I hate it when you say that."
"You know what, this is important. You remember this. I used to be cool!"
Keith has sacrificed a lot, not only for his family, but for the truth. He accused Jake Kane of murdering his own daughter, even though Jake was a billionaire. After being kicked out of the sheriff's office (and being replaced by Lamb), he didn't move away from Neptune (though his wife wanted him to). He stayed and became a private detective. And even when Lianne left him, he didn't break down and compromise his morals.
There is only one thing he would compromise his morals for: Veronica, his daughter. After all, he walked through fire (literally) to save her.
But there is tension underneath their relationship. After the Lilly Kane murder was solved, Keith was vindicated somewhat, but there is still unease in the Mars household. First, there was her tumultuous relationship with Logan, at the end of which Keith had to forcibly throw Logan out of the house. And then there was Veronica's secret trips to Duncan's suite — something Veronica didn't think her father would notice. He notices more than she gives him credit for.
Like when the dead body of David "Curly" Moran washed up on shore with "Veronica Mars" written on his hand and Veronica said nothing to her father about it. When Keith found out and called her immediately to check where she was. She deftly lied, but he demanded proof, no longer trusting her words. And when Veronica helped her boyfriend sneak out of the country with his baby, Keith finally confronted her about how he could never trust her again. Hopefully, he has since rethought his position, since she did help save his life from Liam Fitzpatrick. However, he may feel that some of that trust is misplaced, as he recently learned about her STD and the various activities she did last year that she never told him about (the only reason he knew about it was because of a certain French attorney during Aaron's trial). But he's still very protective of her. How protective? Enough to grab that attorney's tie and threaten him. Or that could have been because of his hate for air quotes.
Woody Goodman was able to persuade Keith to run for sheriff, but he lost just as Woody became county supervisor (or "mayor"). Woody's plan for incorporation would mean Keith would become chief of police, but Keith decided that Neptune is better unincorporated. Though he does help Woody out sometimes, Woody crossed the line when he called Keith to pick up an unconscious callgirl he had spent the night with — and then Woody promptly told the police that it was Keith who had slept with her. Though Keith straightened the press out and the incorporation plan was voted out, he was still suspicious of Woody. And rightly so, as it turned out Woody wasn't a good man, but a pedophile. Keith, with a little help from Vincent Van Lowe, managed to track him down and capture him.
Keith has had several relationships, but they've ended badly. With Guidance Counselor Rebecca James, Veronica was still not ready yet, so he broke it off. With Alicia Fennel, Wallace's mom, he was truly happy — but it all came crashing down when he found out her real identity and she broke up with him. It's not known now if their relationship can be mended.
Now that the bus crash is solved, the only questions that still plague Keith are the secrets that Veronica keeps. But despite those secrets, she is still the most important person in his life and vice-versa, as her hug attested when she thought he was dead. Now, the only question is: what's in that briefcase that would make him ditch his daughter at the airport?
All bios: 3.20 3.17 3.14 3.07 3.06 3.02 3.01 2.22 2.21 2.20 2.13 2.01 1.22 1.18 1.05 1.01
Enrico Colantoni plays Keith Mars.