David St. John's archive contains a wealth of notes, drafts, and publication materials for all of his collections of poetry, as well as for prose works, individual and unpublished poems, and collaborative works. These materials show both the breadth and depth of St. John's work—in each of the various genres of writing he produces, he repeatedly returns to individual pieces to revise, reshape, and improve them. This process is evidenced by the number of heavily annotated drafts and multiple versions of works present in this archive.

St. John has been active within the poetry community for his entire career. In addition to mentoring young poets as a professor at USC, St. John regularly gives readings and interviews, arranges and hosts readings by fellow poets, serves on a rotating slate of professional, journal, and prize committees, and maintains a lively correspondence with many poet and artist friends. In this collection, these relationships are perhaps most interestingly expressed in the series of introductions St. John has given for readings by others, in which he describes their personal connections to him and places them within the larger poetry community. The archive also includes interview transcripts and recordings, scripts for and recordings of readings and lectures, agendas and appointment calendars, and materials from various committees. His correspondence melds personal and professional, and includes letters from Norman Dubie, Mark Irwin, Donald Justice, Galway Kinnell, R.B. Kitaj, W.S. Merwin, Howard Norman, Adrienne Rich, and Mark Strand, among many others.

A unique feature of this archive, and further evidence of St. John's key role in the poetry community, is a large amount of material by fellow poets Larry Levis and Philip Levine. The three first converged in Fresno, California, where St. John and Levis were students and Levine was a professor at California State University, Fresno. After Fresno, both St. John and Levis went to the Iowa Writers' Workshop. They and Levine remained good friends and critics of one another's work until Levis's untimely death in 1996. St. John and Levine subsequently collaborated to publish four posthumous collections of Levis's poetry and prose, as well as a documentary about his life, A Late Style of Fire. Materials relating to the compilation of these five works are included in this archive. The collection also includes correspondence from both Levis and Levine to St. John, poetry and prose by Levis, and works by St. John with constructive comments by Levine. Additional related materials are in the Philip Levine collection at the New York Public Library.

In 2023, Susan Weller donated a small collection of poet Roberta Spear's manuscripts, poem drafts, correspondence, and other material to be added to the David St. John papers because of the collection's focus on various Fresno poets. Roberta Spear (1948-2003) earned a BA and an MA at California State University, Fresno. Philip Levine, who was Spear's teacher and lifelong friend, edited a posthumous collection of Spear's work, A Sweetness Rising: New and Selected Poems (2007). Spear's other published books of poetry include The Pilgrim Among Us (1991), Taking to Water (1984), and Silks (1980).