ESPN has tapped creative agency darling Droga5 to support a new brand campaign as it grapples with changing behaviors in TV viewing.

The media company, which is majority owned by Walt Disney Co., has hired the agency to handle a new campaign for its overarching brand and “SportsCenter.” The campaign, slated to launch in the coming months, is aimed at today’s more diverse and distracted sports fan.

“As sports has evolved, we have an opportunity now to speak to a wider audience than just necessarily men,” said Ed Erhardt, president of global sales and marketing at ESPN. “Today’s sports fan is more diverse, clearly more female [and] more interested in a wide variety of sports.”

The traditional definition of sports has broadened to include everything from esports to cycling to baseball, he said. ESPN is also looking to reach viewers who can now access sports content from various online platforms.

ESPN also recently announced that it will start its own streaming service early next year. It won’t be a replica of the regular ESPN channel, but does plan to show Major League Baseball and National Hockey League games.

“Technology has clearly allowed sports fans, through social and a wide variety of other means, to consume and find sports information in many places and in many ways,” Mr. Erhardt said. “We’re tuning into that different audience with the work we do.”

ESPN has been among the media companies reinventing as habits shift from traditional TV viewing to online consumption.

Disney Chief Executive Bob Iger first acknowledged “some subscriber losses” at ESPN two years ago. Since then, cord-cutting and consumers downgrading to cheaper cable TV packages have continued to eat in ESPN’s traditional customer base.

ESPN has lost 2.8 million subscribers since August 2016, not including streaming services, according to Nielsen’s August 2017 estimates. The network still has almost 86 million subscribers, based on Nielsen estimates. ESPN said it has 87.2 million subscribers, including subscription streaming services.

TV networks are racing to offer new streaming services—and ways to watch shows with fewer or no ads—to appeal to an increasingly fickle viewer with more choices. ESPN is available through a number of streaming services, such as DirecTV Now, Hulu, Sling, Sony Vue and YouTube TV.

As ESPN spreads its programming and content across digital platforms, the network is banking on a new ad effort to help it stand out in a sea of sports programming competition, as well as create brand consistency in a fragmented TV marketplace.

“I’m trying to move our overall language from channel and network to platform,” said Mr. Erhardt.

Droga5, whose portfolio includes work for Chase, MailChimp and Pizza Hut, is tasked with helping ESPN create a brand that resonates across audiences and on various media platforms.

But it won’t be easy.

Longtime incumbent Wieden + Kennedy set a high bar. The independent agency, which worked with ESPN for over two decades before parting ways late last year, was behind the network’s celebrated “This is SportsCenter” campaign.

Despite its plans for a marketing revamp, ESPN won’t completely abandon the ad, said Mr. Erhardt.

Wieden now works with ESPN rival Fox Sports, which this month unveiled a new ad for the start of college football.

Write to Alexandra Bruell at alexandra.bruell@wsj.com