Robert J. Zimmer, the 13th President of the University of Chicago, will step down from the office of President on July 1, 2021, leaving a role he will have held for 15 years, according to emails sent to members of the university community on Thursday morning.

Zimmer will transition into a new role as Chancellor of the University and serve as a Trustee, according to his Thursday email. Zimmer was slated to serve as President until 2022 but announced his intention to step down early, citing health concerns. In May, Zimmer underwent successful emergency surgery for a brain tumor.

The position of Chancellor, which has not existed at UChicago for nearly 60 years, “is meant to address the current situation and is not reflective of a permanent change in the structure of University leadership and governance,” the President stressed in his email. Between 1945 and 1961, the University of Chicago’s board decided to designate the University’s head as “Chancellor,” as opposed to “President.” The decision was reversed in 1961, and since then the position of Chancellor has been left vacant.

Zimmer presided over a tumultuous period in the University’s history, overseeing a vast expansion in the University’s selectivity, visibility, and donor pool. At the heart of Zimmer’s prolific tenure was his ability to fundraise. At the end of fiscal year 2006, the University of Chicago’s endowment was $4.6 billion; by 2019, it had grown to $8.5 billion. Milestones from Zimmer’s tenure include securing a $300 million donation from alumnus David G. Booth (M.B.A. ’71), then the largest business school gift in history; overhauling undergraduate admissions via the adoption of the Common Application; and taking drastic steps to remake the face of campus, from the construction of new dorms to conference centers. Zimmer was also instrumental in securing Jackson Park as the site for the future Obama Presidential Center in 2016.

President Zimmer also spearheaded the launch of the 2014 Chicago Principles, which committed the University to the freedom of expression. Zimmer and his administration have since taken a very public role in defending and promoting these ideals. As of spring 2019, 63 other universities have adopted the Principles.

Zimmer’s administration has been criticized by members of the University community. His refusal to recognize Graduate Students United, UChicago’s graduate students’ union, led to a three-day strike in the Spring of 2019, the first-ever graduate student-lead work stoppage at UChicago. Critics of the University of Chicago Police Department occupied UCPD headquarters for 19 hours this summer. And activists have long decried the Zimmer administration’s aggressive development, citing concerns of gentrification and displacement.