It was a year of change that paid off at Weber Shandwick.

In January newly appointed CEO Andy Polansky promoted Gail Heimann to president and chief strategy officer. Three months later, the Interpublic Group of Cos' PR agency launched MediaCo, an aggressive dive into the crowded content space that catapulted it beyond traditional PR.

By the end of the year, the shop had increased revenue 10% and added 16 new clients, including Chobani, Kohls, TripAdvisor, Getty Images and health-trade group PhRMa.

"We've been a consumer powerhouse for many years," said Mr. Polansky. "This year we built on that. We developed other aspects of the business."

The shop encouraged more collaboration across practice groups, he said. That might mean bringing the health practice's Element Scientific Communications comprised of PHDs with medical-science expertise into more consumer-marketing discussions and vice versa.

While collaboration is a long-term focus, the real growth driver of the year, according to Mr. Polansky, was MediaCo. The group invested millions in headcount alone and launched with a cadre of new staffers foreign to the PR-agency world, such as brand planners, editors, user-experience designers, writers, SEO experts, media planners and producers. Since its launch, content has inched its way into nearly every client initiative, the agency said.

"They were integrating paid, owned and earned before that became part of the lexicon," said Christine Cea, senior director of marketing and communications at Unilever. Weber works on a larger portfolio of Unilever brands than any other PR and social shops in the U.S., spanning food and personal care, as well as a new corporate project called Project Sunlight which encourages people to live more sustainable lives. "They understand platforms, how people use and consume content and how to amplify across channels," Ms. Cea said.

When Project Sunlight launched on November 20, the agency set up a media command center at its new office space in Manhattan. For the next few days, a group of executives from Weber's MediaCo, Unilever's media agency Mindshare, Twitter and the client gathered in the space and pushed out content around the new initiative. At the end, the group saw five times the benchmark engagement level on Twitter, said Ms. Cea.

In addition to creating editorial content for clients like Verizon Wireless, Weber also boasted digital-advertising assignments typically fit for creative or digital ad shops. For example, the agency produced a video series for client Mattel's Fisher Price brand called "Share the Joy." The campaign, intended to reach millennial moms, led to a 50% increase in the brand's digital spend before the holiday season, the shop said. Similarly, for Diet Pepsi, the group videotaped an undercover Josh Duhamel pretending to be a supermarket employee and then posted the video on YouTube, garnering more than 3.3 million views in the first week.