Mr. Speirn has led the organization since 2006. He said in a letter that he does not plan to retire but will instead continue to focus on ways to help vulnerable children and families.
"He's had a lot of accomplishments here, a lot to be proud of, and I think he likes the idea of going out on the top of his game," said Joanne Krell, vice president for communications, in an e-mail. Mr. Speirn will be 65 at the time of his departure.
In a statement, Rod Gillum, Kellogg's board chair, said Mr. Speirn had strengthened the foundation's work aiding needy families by "creating new systems that provide better, more affordable food, higher-quality education options, and clear paths out of multigenerational poverty."
The foundation also made explicit long-term commitments to certain cities and states, Mr. Gillum said, and announced a $75-million* multiyear pledge to promote racial equity. Like many philanthropies, the foundation was also forced to trim its operations during the economic downturn, including closing several overseas offices.
Before he joined Kellogg, Mr. Speirn served as president of the Peninsula Community Foundation, the California grant maker now known as the Silicon Valley Community Foundation. His first job in philanthropy was in corporate giving at Apple, in the 1980s, according to an interview on the Kellogg Foundation's Web site.
*An earlier version of this story misstated the size of Kellogg's pledge.