He was the son of Dorothy and Allen Cassity.He grew up in Jackson and Forest, Mississippi.He graduated from Millsaps College and Stanford University with a master's degree.
From 1952 to 1954, he was drafted and stationed in Puerto Rico.He attended Columbia University on the GI Bill, and received a master's degree in library science in 1955.
He worked for the Jackson Public Library and then moved to South Africa.He worked at the Robert W. Woodruff Library at Emory University, from 1962 to 1991.He also cofounded the Callanwolde Readings Program, which highlights poets and writers, with poet Michael Mott.
He is buried in Forest, Mississippi.His papers are at Emory University.
Devils & Islands, Cassity’s 10th collection, reinforces the image of the dapper Southerner as a satirist, and, in the words of National Endowment for the Arts Chairman Dana Gioia, ’73, MBA ’77, perhaps “the most brilliantly eccentric poet in America.”