LISLE, Ill. — Troy Clarke will become president and CEO of Navistar International Corp., parent company of school bus manufacturer IC Bus.

Clarke, currently Navistar's president and chief operating officer, will assume the CEO role and will join the company's board on April 15.

Lewis Campbell, who has served as executive chairman and interim CEO since August 2012, will step down from those positions and from the board.

James Keyes, who has served as a board member since 2002, will become non-executive chairman, also effective April 15.

"Over the past six months, Navistar has made significant progress on many important fronts, including on our three near-term priorities: improving quality, meeting each of our clean engine launch milestones, and delivering on our 2013 operating plan," Campbell said. "When I assumed the interim CEO role last August, I was prepared to stay as long as necessary to oversee the company through a transition period, and today I am pleased to announce our turnaround is firmly underway and our return to profitability is clearly in sight."

Campbell added that he is "also delighted that the board and I have decided that Troy is the right executive to lead the company forward at this time, and I am confident Navistar will continue to build on its momentum — improving performance and quality for customers and creating shareholder value."

Keyes thanked Campbell for his contributions to Navistar.

"He stepped in during a challenging period of transition for the company, and his leadership was critical in helping align our board and management around a clear path forward," Keyes said. "The board is also extremely pleased to name Troy as chief executive officer. He is a proven leader and has been a valuable asset to the executive team since joining the company in early 2010."

Clarke said that he is honored to take on the role of CEO and to join the Navistar board.

"In six short months, we have made significant progress on our turnaround, and I want to thank Lewis for his guidance and leadership during this period," Clarke said. "Working together, we have implemented a number of important actions to set Navistar on the right path, and the company now has a strong platform to build upon going forward."

Before serving as president and chief operating officer of Navistar, Clarke was president of Navistar Asia Pacific. He joined Navistar in January 2010 after a 35-year career at General Motors, where he held numerous leadership positions, including president of General Motors North America.