Duveneck School is searching for a new principal following Monday's unexpected resignation of John Lents, effective June 30.
Lents, longtime principal at Addison School who moved to Duveneck last fall, is relocating to St. Louis for family reasons.
A search for Lents's replacement will begin immediately, school officials said.
In a message to Duveneck families, Lents said, "Without question, I fully intended to make Duveneck my professional home. However, even the best-laid plans must be rewritten at times."
Lents explained that his husband had received an unexpected job offer with a major hospital in St. Louis.
"The dilemmas created by this opportunity have been significant as we've explored their impact upon our personal and professional lives," he said.
Palo Alto School Superintendent Kevin Skelly said, "While we are sad that this talented principal is leaving, we will work hard to find a replacement worthy of this great school in a timely manner."
Lents began his education career 34 years ago at the American School of Kuwait.
Before coming to Palo Alto 11 years ago, he worked at the American School of Budapest and in schools in the St. Louis and Kansas City areas.
After years at Addison, he moved to Duveneck a year ago to replace Kathleen Meagher after she was named the district-wide director of elementary education.
At the time, Skelly said Lents had "expressed a desire for the rejuvenation and energy that comes with leading in a new environment."
Lents's replacement will be the Duveneck community's fourth principal since 2006.
In the message to families, Lents expressed "deep appreciation for your understanding and for the opportunity to work with you, but also with deep regret that I won't be here to see this community continue to grow and flourish."