[6] At the turn of the century, Headmaster George D. Pettee led the entire student body to the Pan-American Exposition in Buffalo, New York, in 1901.

[6][7] A few years later in 1908 Headmaster Harry S. Peters led University School during two World Wars, the Great Depression and, in 1926, to the 36-acre (150,000 m2) campus in Shaker Heights.

[6] That same year Headmaster Harold L. Cruikshank oversaw the building of the Hanna Wing on the Shaker Campus and guided the school through the end of World War II to the beginning of the 1960s.

Under the leadership of Roland P. McKinley, the Upper School moved, in 1970, from Shaker Heights to nearly 200 acres (0.81 km2) of meadows and woodland in Hunting Valley.

[8] With the support of the US community, Conway Hall on the Shaker Campus and the William S. Kilroy '43 Field House in Hunting Valley were built during Hawley's tenure.

Murray led the School in the fundraising and construction of a nearly $100 million, 52,000 square-foot academic wing, which features classrooms and interactive technology.

[10] In the wake of Bryan's departure, dean of faculty and English teacher Patrick Gallagher was named interim headmaster by the school's board of trustees.

[11] On September 22, 2018, the school's board of trustees announced that Patrick Gallagher would officially assume the role of headmaster, following an eight-month search period.