School of Medicine Dean David Kessler will leave July 1 to become dean of the University of California-San Francisco’s school of medicine, UCSF Chancellor J. Michael Bishop announced last week.

Yale President Richard Levin will appoint a search committee to replace Kessler, who served as dean for six years after nearly seven years as commissioner of the Food and Drug Administration.

“This is really not an easy step for me,” Kessler said. “I love Yale. I make this decision with far more confidence when I look at the progress that we’ve made during the last six years.”

As dean, Kessler oversaw the School of Medicine through a major growth spurt, which included over $500 million in investments from the University, a 25 percent increase in laboratory and clinical space, and plans for a $35 million Pfizer clinical research facility.

He came to Yale after serving as commissioner of the Food and Drug Administration under the first Bush and Clinton administrations, where he was known for his aggressive efforts to regulate tobacco, require “nutrition facts” labels on food and speed up procedures for approving new drugs.

Kessler will arrive at UCSF in the midst of the medical school’s development a new campus on Mission Bay, which he called an enormous but wonderful challenge.

Neurosurgery chairman Dennis Spencer will serve as acting dean until Kessler is replaced, Levin said in an e-mail to medical school faculty, students and staff following the announcement.

Bishop said Kessler’s record as a leading national public health advocate and academic figure would serve him well during UCSF’s development of a new campus.

“We’re very pleased that Dr. Kessler will be assuming leadership of the UCSF School of Medicine at this significant point in the school’s history,” Bishop said in a press release. “He is a distinguished public servant and academic leader, and I believe that his extensive experience in the leadership of both public and private institutions will serve UCSF well.”

Prior to his FDA appointment, which began in 1990, Kessler, 52, served as medical director of the Hospital of the Albert Einstein College of Medicine in the Bronx. Kessler, who holds a law degree, also taught food and drug law at the Columbia University School of Law.

Despite his stint in government, Kessler said he sees his major work as an academic.

“I try to share with young people what it’s like taking on these big challenges,” he said.