Rick Kern, Getty Images for Samsung

Todd Pendleton, the executive behind Samsung's successful "Next Big Thing" campaign, is looking for his next big thing -- but it won't be at Samsung.

Pendleton, who has served as chief marketing officer for Samsung's US mobile business for nearly four years, notified his colleagues this week that he's leaving in April, people familiar with the matter told CNET. Some of his direct reports have also left Samsung or have been transferred to other departments, the people said.

On Friday, Samsung in a statement thanked Pendleton "for lending his creativity and inspiration to the mobile business at Samsung and said it's "excited for the future." The company didn't say who will replace Pendleton in the interim or on a permanent basis but noted he's playing an advisory role until April. Here's the full statement:

Over the years, Samsung has nurtured talent internally and recruited some of the brightest minds in the business to build an even stronger marketing organization. As those teams have grown, we have seen our brand presence increase and consistently performed well in the US with American consumers embracing our products. Samsung continues to strive for innovation in marketing and we've built a marketing Center of Excellence that will drive brand strategy, creative, digital and media across all product categories. We wish Todd well, and have thanked him for lending his creativity and inspiration to the mobile business at Samsung. We are excited for the future and look forward to bringing engaging campaigns that will further surprise and delight our customers.

Pendleton didn't respond to a request for comment.

Pendleton has been lauded as one of the people central to Samsung's fast rise in the mobile market. His team spearheaded the popular , which mocked Apple's devices and fanboys and helped Samsung's Galaxy S3 become the best-selling smartphone in the world, at least for a time. Because Samsung convinced all US wireless carriers to release the device at the same time under the same branding, Pendleton and his team -- along with ad agency 72 And Sunny -- were able to create one major campaign instead of having to market multiple models of the Galaxy smartphone.

Pendleton, testifying during Samsung's patent-infringement trial against Apple last year, said it was his team, and not any copying of the iPhone, that helped Samsung become No. 1 in the smartphone market. Samsung had become the "most viral" brand in the world based on the number of social-media followers and shares, Pendleton told the jury. Today, Samsung Mobile (@SamsungMobile) has 10.6 million Twitter followers.

Samsung has been struggling recently, though. After leading the smartphone market for the past four years, Samsung has seen its profit slide as customers have defected to rival Xiaomi in China, Micromax in India and Apple nearly everywhere else. In the global smartphone market, Samsung tied with Apple as the No. 1 vendor in the fourth quarter of 2014 -- a competitor it had crushed not too long ago. Samsung on Sunday showed off the new smartphones, the Galaxy S6 and Galaxy S6 Edge, that it hopes will help it regain its footing.

Pendleton is the latest in a string of executive departures that have plagued Samsung over the past year. Executive turnover isn't surprising at an organization Samsung's size (it employs nearly 300,000 people around the globe), but the South Korean company has been hit by several high-ranking departures in the US. Many have exited the mobile business, but others have left the electronics arm responsible for TVs and home appliances.

Also adding to the problem was a plan by Samsung to relocate its US mobile marketing group, business-to-business operations and some other teams from Richardson, Texas, to a new facility in New York's Meatpacking District or to Samsung's North American headquarters in Ridgefield Park, N.J. That led to many departures in mid-2014. Pendleton was part of the team originally slated to move, though Samsung since then has pared back its plans.

Other departures from Samsung's US mobile business last year, which CNET News first reported, included Seshu Madhavapeddy, the senior vice president of product and technology who was responsible for development and delivery of Samsung's mobile devices; and Nanda Ramachandran, the vice president and general manager who led strategy, marketing, and product management for Galaxy tablets, the Galaxy Gear smartwatch and Samsung HomeSync.

Update March 6 at 1 p.m. PT: Added comment from Samsung.