O'Sullivan's poetry can be called both learned in its references to diverse Western cultural items or traditions, as is noticeable in 'Blame Vermeer', 'In times of thanks and praise', 'Talking of stone' or '1919', and as thoroughly familiar with and sharply observant of the particularities of his homeland, as demonstrated in 'July, July', 'River road, due south' or 'Late praise for Nurse Smythe'. Though at times handling the connotative power of a theme, of language or a word in a playful mood, as in 'Check-up', 'Saying begins it' or 'The monastic life', his poems never become flippant or assume the arbitrariness of postmodernism because they derive from an essentially philosophical and sceptical mind, which becomes manifest when a poem addresses fundamental questions like life and death ('Right on'), love and time ('Seeing you asked', 'Simply') or religious belief ('Dark night on the lake'). Structured in the characteristic O'Sullivan manner, realistic and descriptive openings are very often followed by an interjection, a speculation or a reflection lending them depth, and in turn leading to a summarizing conclusion, as in 'Small talk' or 'Blond ink'. No preference is given to a particular form as four-line stanzas, often rhymed, or two line-stanzas with an even rhythm stand next to free line examples. Such mentally unfolded and formally organized images and thought processes often underpinned by employing opposites convey the poet's moral stance, yet this at the most ends on a warning note such as: "It will happen next", in 'Blame Vermeer', or: "The moon is gone and the axe grows bigger and bigger", in 'No time for portents'. However, one would miss a central aspect of O'Sullivan's poetry if one does not note their cleverness, their wit, as is found in the allegorical bathos of 'The monastic life' or the employment of kiwi-phrases, epithets and similes in 'Check-up' or 'The grieving process', the latter two being of a more personal nature. In the poet's reading a strong male voice comes across that hardly varies in sound, tone, speed, emphasis or musicality, inviting the reader to attentively follow the narrative lines and their structures, a poem's conceits and spontaneously evoked images as well as sudden shifts of phrase or tone. The poet holds his own personality as much back here as in his work and still speaks in a unique and unmistakable voice.
His recording was made for The Poetry Archive on 9 September 2008 at The Audio Workshop, London and was produced by Richard Carrington.