In 1983 he published two collections of essays, The Lyrical Truth (서정적 진실) and Modern Poetry and Its Practical Criticism (현대시와 실천비평).

He was a guest lecturer at the University of California, Berkeley in 1995, discussing Korean literature for the Department of East Asian Languages.

[3] O Seyeong's volume Night-Sky Checkerboard was translated into English in 2016, published in the United States and listed by the Chicago Review of Books as one of the twelve best poetry collections of 2016.

[4][5] O Seyeong's early works contained significant amounts of "deconstructive" poetry, leading him to be classified as a modernist poet.

‘Namelessness’ is a Buddhist word that describes a state when the mind has not yet reached intrinsic enlightenment, but rather captured by desires and ego.

The Chicago Review of Books said that O Seyeong's “attention to detail, and his ability to shift back and forth between scopes both grand and minuscule, provide a sense that his poems are inextricably linked to something larger,” noting that his poetry collections “work very much obsessed with existence, the building and destruction of nature, business, war, and industry.