Be the culture you want to encourage.
People entering a new community (that's what your team is) typically take a couple days to feel out what the existing norms are, and will adopt those norms -- go along to get along -- as long as the norms are reasonably in line with their values.
That is, you might not get someone who wears a burqa to switch to hotpants, but you might convince her to wear a green one instead of a blue one, or to wear a baseball cap on top.
A developer who's passionate about writing provably mathematically correct software for space shuttles might have difficulty adapting to a "move fast and break things" mindset, but s/he might be willing to adjust from a waterfall process to one that involves more frequent customer feedback. Determining what sort of adjustments people are willing to make is an important part of the hiring process.
The exceptions to the "adopt existing norms" rule are people who are immature or assholes. See also AnimalMuppet's comment about hiring grownups.
Culture is least sticky at the earliest stages when there are only a few people in the existing community, and it hasn't been established for long. The more people you have in the community and the longer it's been established, the more inertia the culture has, so the personality differences of a single addition are less likely to change it significantly unless they're a truly raging asshole and you let them stomp all over people for too long.
At the beginning, be VERY careful about those first few hires. The culture they adopt will basically be the culture of your team for a very long time. You're more likely to have to spend a lot of time setting an example, speaking explicitly about the norms you want to enforce, and quietly taking people aside to correct them when they violate those norms.
