After 12 years, Greg Schmitz is leaving as principal of Justin-Siena High School, according to officials from the private Catholic school in north Napa.

Justin-Siena Chief Executive Officer Joseph Bracco said Schmitz will take a one-year sabbatical.

“Schmitz will be stepping down from his position this school year and will have the opportunity to return in a different position when he returns,” said Bracco.

Justin-Siena serves approximately 600 students from Napa and surrounding cities.

The school, which was originally Justin High School, was founded more than 30 years ago. In 1972, it merged with Siena High School for girls, run by the Dominican Sisters of San Rafael. The school is run by the Christian Brothers, which also runs De La Salle High School in Concord and De Marillac Middle School in San Francisco.

Bracco said Justin-Siena is currently searching for a new principal.