innovative American educator best known for his “platoon” system of alternating two groups of students between classroom and recreational or vocational activities.

Wirt graduated from DePauw University in 1898, attended graduate school there and at the University of Chicago, and then went to Europe to study educational methods. He began his professional career while in college in Indiana; he was superintendent of schools in Redkey (1895–97), taught mathematics at Greencastle (1897–99), then served as superintendent at Bluffton (1899–1907). He introduced his system at Bluffton, but it was as superintendent of the Gary public schools (1907–38) that Wirt attracted national attention with his idea of splitting the student body into platoons. In its time Wirt's idea, known as the Gary Plan, caused the city to be known as a centre for progressive education.

Wirt intended his plan to make more efficient use of school facilities. It led to greater emphasis on recreational and vocational activities in school, lengthened school hours from six to eight, and encouraged teachers in subject-area specialization. In 1914 New York City hired Wirt as an adviser to implement his system there, but controversy among New York educators over the Gary Plan led to its repudiation in 1918. The number of schools following Wirt's program dwindled from more than 1,000 (in more than 200 cities) in 1930 to a handful within two decades. In the 1930s Wirt charged that public schools were spreading communist propaganda. This led to a congressional investigation that found no evidence to support his allegations.