O’Brien is best known for performance art actions in which he uses endurance and un-simulated injury to explore his experience of living with cystic fibrosis, a chronic genetic illness.
For example, Mucus Factory of 2011 (which lasts between three and six hours) is structured by a cycle of actions through which O’Brien performs versions of therapeutic interventions required to maintain his health and slow the progress of cystic fibrosis.
[3] His works also tend to borrow the styling, actions, and paraphernalia of sadomasochistic practices, including genital piercing, autoerotic asphyxiation, or mummification.
His use of imagery derived from BDSM is often in direct dialogue with the work of the late Bob Flanagan, a pioneering artist who similarly used pain and endurance to explore his experiences as a person with cystic fibrosis in the 1980s and 1990s.
[7] His work has been presented throughout the UK, Europe and the USA including Spill Festival (London), Kapelica Gallery (Ljubljana), Abrons Art Center (New York), ONE National Gay and Lesbian Archives (Los Angeles), Tate Britain, London, In Between Time Festival of Performance (Bristol), Chapter Arts Centre (Cardiff), and Grace Exhibition Space (New York).