Brian Napack will step down as president of Macmillan at the end of the year and work with the publishing company on an as needed basis to help ensure a smooth transition into the new year, Macmillan CEO John Sargent told employees in a memo. Napack joined Macmillan in May 2006, and, during that time provided “strong leadership and effective management” for both Macmillan’s trade and educational operations, Sargent said. “His leadership on the digital side of our business has positioned us to compete in a world that is being defined by eBooks, mobile devices, digital learning, digital marketing, online retail, and more. His work on behalf of the industry has made a major impact in Washington and around the country,” Sargent wrote.

Sargent said Napack decided to leave because he had concluded the time is right to pursue other opportunities, noting his decision is a “sad one for me.” In his note to employees, Napack wrote: “Over the past few months, I have been thinking a great deal about my goals for the future and about the many opportunities that exist in our rapidly changing markets. Simply said, I have decided to pursue some of these business opportunities from a different perspective.”

According to Publishing Trends, which first reported the news on Napack’s departure, he will announce his new plans early in 2012.