Dr. Cooper joined the Department of Urology in 1999 and serves as director of the department's Division of Pediatric Urology.

His clinical research interests include vesicoureteral reflux (VUR), bowel and bladder dysfunction, neurogenic bladder, and hydronephrosis.

His early work in the study of VUR helped demonstrate what has now become an accepted practice of more selective and limited use of antibiotics in children with VUR. Later work demonstrated the importance of noting bladder volume at onset of VUR, which serves as an independent prognostic factor for VUR resolution and breakthrough UTIs. He also produced the first machine-learning neural networks that incorporated multiple individual variables to predict VUR resolution.

Additional work identified the distal ureteral diameter ratio (UDR) as another independent prognostic factor for resolution and breakthrough UTIs. UDR was demonstrated as a more objective and reliable measurement than grade. Multiple national and international publications subsequently reproduced his UDR findings.

In 2019, Dr. Cooper received the Societies for Pediatric Urology Clinical Research Prize for developing and patenting devices for home use that attach to a catheter to record bladder pressure and volume. These devices were developed to help children with neurogenic bladder avoid decline in bladder function and kidney injury. Later he received a research grant from the Southwest National Pediatric Device Innovation Consortium for continued development of these devices.

In 2022, the Urology Care Foundation of the American Urological Association recognized Dr. Cooper's career-long research contributions "to enhancing the treatment of children suffering with urologic conditions and improving their quality of life" with the John W. Duckett, Jr., MD, Pediatric Urology Research Excellence Award.