Callum will lead global design of all concept and production vehicles for the Ford and Lincoln brands.
He will report to Raj Nair, Ford's global head of product development.
Since 2006, Callum has had overall responsibility for the design of all cars and trucks designed in Ford's North and South America studios and for Lincoln. Vehicles designed under his guidance include the new Ford Fusion, Explorer, Mustang, EcoSport and Lincoln MKZ. Prior to his Ford job, Callum was based in Hiroshima, Japan, where he headed Mazda design from 2001 to 2006.
For the past five years, Jim Tetreault has been responsible for Ford's North America manufacturing operations with more than 30 manufacturing plants. Tetreault played a key role in ongoing efforts to improve manufacturing flexibility and efficiency, the company said.
He also oversaw a product expansion in the region and the company's conversion to global platforms. Tetreault also served as vice president, Ford of Europe manufacturing, for three years and held numerous positions in plant operations and staff.
"Jim's strong leadership and attention to detail will be missed," said Joe Hinrichs, executive vice president and president, The Americas.
Succeeding Tetreault at the helm of Ford's North America manufacturing operation will be Bruce Hettle, 52. Hettle is currently executive director of global vehicle operations manufacturing operations.
Hettle, who has worked for Ford for 27 years, has led the company's global manufacturing engineering organization for vehicle operations since 2008. In addition to other leadership roles, he has served as director of Ford's manufacturing business office, and plant manager for Wayne Stamping and Assembly and Edison Assembly. He will report to Hinrichs.
Mulloy was appointed to his current position in 2005. He has been responsible for global labor policy and negotiations covering Ford's approximately 117,000 hourly employees. He led the company's successful 2007, 2009 and 2011 contract negotiations with the UAW. His career includes a variety of positions in human resources and labor affairs, including serving as the company's most senior HR leader in The Americas, Australia and Manufacturing.
"Marty's enthusiasm and love for Ford is infectious," said Fleming. "His dedication to collaboration and inclusiveness has strengthened our relationships with the UAW and our hourly employees around the world. "
Mulloy will be replaced by Bill Dirksen, who has been executive director, U.S. Labor Affairs, since 2007.
In his new role, Dirksen, 53, will be responsible for labor negotiations and labor policy globally for the company's union employees. He joined Ford Motor in 1985, and has served as the senior human resources leader at Ford Credit, manufacturing and quality, and Australia prior to moving to the U.S. Labor Affairs position seven years ago.
Ford credited Dirksen, working with Mulloy, for playing an important part in the company's 2007, 2009 and 2011 UAW negotiations. Dirksen will report to Fleming and to Felicia Fields, group vice president, Human Resources and Corporate Services.
Ford also announced the election of Steven Armstrong as president, Ford South America, reporting to Hinrichs.
For the past 18 months, Armstrong, 49, has been president of Ford's Brazil operations, leading all aspects of the company's largest business unit in South America. He previously served as COO of Volvo Cars.
Throughout his more than 25-year career, Armstrong has held a variety of senior management and purchasing positions with Jaguar, Ford of Europe and Volvo.