Read on Crain's

A hot company with its eyes set on an IPO or another big exit can double or triple its staff within the space of a year. Manhattan-based MediaMath, a software-based marketing company and one of Crain's 50 fastest-growing companies last year , had about 175 employees at the beginning of 2013; it now has 350. But growing a company is not just about adding talented staff. It's about being able to make sure the culture that won you the early success grows along with the company. Crain's asked CEO Joe Zawadzki about the tactics executives can use to retain a culture while the company is adding staff.

How have you done that much hiring in one year?

I still wonder. Part of it was through an acquisition [of Akamai Technologies], so that was about 65 people all at once. It felt quite organic because it was a data-management company—it was a product extension for them and close to the core of what we did. Everybody woke up and thought about the same things, so a lot of that integration was highlighting the benefits of the acquisition and working for MediaMath.

A little more than half was just organically adding people. At the fastest pace at the end of last year, we added a couple of people a week. A lot of the focus was on the recruiting process: People were focused on bringing on the skill and will. We interviewed for "math values."

You've said what makes MediaMath different is the people you hire and the environment you create for them to work together. How do you create that collaborative environment?

There is an expectation that the team's win is everybody's win; that it's hard for one department or one person to make the requisite things happen. We do a lot of positive reinforcement around this is how things get done.

We pay attention to collaboration in both physical space and virtual space. There's the notion of having a variety of workspaces for the different kinds of work people do. … There are lots of huddle areas, and also workspaces that are reflective. We have a regular hackathon. One of the apps that people built was an always-on virtual window into all of the offices.

We think about how to cross-pollinate different cultures; we just hired a woman who was running a lot of Google Japan. She's come over to the New York office to start a global best-practice team.

What insights did you have as you worked this year on scaling your culture?

It's always been about people. Your ability to influence the organization is really around the people elements of the business. In a startup, everybody knows what everybody else is doing. [Then, as you grow] you start realizing that more and more of the work is done by the teams. You focus on empowering the teams that are working on important priorities.

You codify what "good" looks like, and communicate how people have been successful in the organization.

How do you communicate the goals and the culture?

We create a "true north" strategy document. It gets updated between the quarterly business reviews, and it lasts a year or a year and a half. It gets reinforced in a quarterly business update, and we tie it in by saying, "Here's what we said from a high-level perspective, and here's how that ties in with what happened." We move up and down the slide of strategic thinking and tactical implementation.

Do you have any advice for an entrepreneur scaling up?
You can't spend enough time on the people and cultural questions. It is the responsibility of the senior leadership. … Create performance indicators around culture. Measurements may be imperfect, but you can do it: Take a look at your employee surveys, for instance, and make sure your numbers are heading in the right direction. Define it: What does "good" look like for your organization?