As one of the world's oldest collegiate fraternities, Zeta Psi has historically been selective about the campuses at which it establishes chapters.

[3] The chapter at the University of California, Berkeley (June 10, 1870) made Zeta Psi the first fraternity in the U.S. west of the Mississippi.

The three men formed the core of the first chapter, Phi, but William Dayton was stricken with poor health and left New York shortly afterward for the University of North Carolina at Chapel Hill.

The Phi chapter at NYU persisted in his absence and graduated its first member the next year with George S Woodhull (Φ '48).

By 1988, the Chi chapter was ejected from campus and banned from any formal rush, quietly expiring after over 130 years of existence.

Expansion of Zeta Psi halted as campuses rallied for war and sent companies of soldiers to battle.

Schwerin lay gravely wounded after the bloody Battle of Chattanooga; pinned on the breast of his Union uniform was the badge of Zeta Psi.

A passing Confederate soldier, also a Zete, spied the badge and carried the invalid to medical care and safety, ignoring even the imperatives of war for the sake of his brother.

The worthy badge later passed into the hands of his brother, Max Schwerin (Θ '70), who would one day serve as international president.

Brother John Day Smith (Ε '72) witnessed the incident on the Chattanooga field and later related it to Brother Francis Lawton (Ε '69), who would author the poem "The Badge of Zeta Psi," later set to original music and preserved to this day.

The Eta (Gettysburg, Pennsylvania, chartered in 1861), Psi Epsilon (Dartmouth), Upsilon (UNC), Epsilon (Brown), and Theta (Union) chapters had vanished by the end of the conflict, decimated by fallen brothers or disheartened campuses returning from the shadow of death.

The Gamma chapter—chartered 1861 at the Georgia Military Institute, as the only new chapter during the War—was annihilated utterly by General Sherman's march and existed thus only for those few years of tumult.

The nation was still young indeed even after the end of the Civil War: California had only recently become a State, committing to the side of the victorious Union and contributing its men––though the conflict took place mainly across the continent thousands of miles away.

[9] Even as the physical reach of Zeta Psi made great bounds, so too did the principles underlying its brotherhood.

In 1909, an international publication concerning the affairs of Zetes was first published by Brother William Comstock (Ξ '99) and distributed among the several chapters: The Circle of Zeta Psi.

And all three of his mandates have been amply fulfilled: The Circle is still published and distributed to the brothers of Zeta Psi (and can be read online here); now the General Secretary is assisted in his rounds by chapter consultants, whose function remains the same; and the Zeta Psi Educational Foundation was to be instituted within Brother Comstock's lifetime, though still in the future.

By war's end, the two beleaguered chapters had sent two hundred of the brothers in defense of King and Country; 31 were never to return and many others came home wounded in body and spirit.

Brother Dr. John McCrae (Θ Ξ '94), a serviceman in the Canadian army, who like so many other men did not return at the close of conflict.

But Brother McCrae bequeathed to his fraternity more than even his worthy life, but also a poem which has been preserved in great honor as both a historical and literary work: "In Flanders Fields."

The 19-year-old engineering student from McGill, brother Frederick Fisher was the first Canadian to win the Victoria Cross in the war, the highest British award for valour, for his determined stand at the Second Battle of Ypres.

At the annual convention of Zeta Psi, the brothers adopted a resolution in support of U.S. engagement in World War I, which the U.S. Congress had only declared a few weeks previously: Nor was the pledge mere idle words nor fatuous boasting.

Over one-quarter of all brethren of Zeta Psi would serve during the First World War in foreign lands, and many did not return.

The Directory continues to be published on a regular basis and the modern version is a useful networking tool for members of the Zeta Psi Fraternity.

[11][13][14] Published in 1928, with two later editions, The Story of Zeta Psi contains the detailed history of the fraternity and each chapter founded up to the point of publication.

[15] Zeta Psi, like all conventional university fraternities, operates as chapters at various campuses across North America and the world.

Zeta Psi has chapters in six countries: Canada, the United States, England, Ireland, France, and Greece.

Zeta Psi is modeled after most modern democracies in that they have legislative, judicial, and executive branches of governance.

At one point in time, there were several appointed officers each designated Chi Phi Alpha (ΧΦΑ) of a particular area (e.g. Canada, or the Northwest United States) which served as geographical representatives to the Grand Chapter.