Rooney saved them from relegation from the Championship by a single point four months after taking on the role.
During Rooney's first full season - 2021-22 - the club were docked 21 points for being in administration and EFL breaches, while they were also handed a transfer embargo.
Derby were subsequently relegated to League One and Rooney left in June 2022 with the club still in administration.
He was appointed head coach of MLS club DC United in July 2022 and oversaw just two wins from the final 14 games of the season as they finished bottom of of the Eastern Conference.