Shea started his career in law enforcement with his appointment to the
New York City Police Academy in late 1990. After graduating in the top 10% of his academy class, he was sworn in as a Police Officer in April 1991 and assigned to the South Bronx. As a Deputy Chief in 2013, he quashed an internal investigation into a sergeant with whom he had a mentoring relationship, Juan Duque, and that sergeant's brother, Ruben Duque. Both had defrauded the department of overtime hours and illegally taken patrol cars home. The story didn't become public until 2018. On November 4, 2019, it was publicly announced that Dermot F. Shea would become the 44th Commissioner of the
NYPD. In April 2014, he was appointed Deputy Commissioner of Operations by then Commissioner
William Bratton. Prior to this appointment, he had been a chief commanding the Office of the Deputy Commissioner for Operations. He also commanded the 44th and 50th precincts and the Patrol Borough Bronx Anti-Crime Unit. On April 16, 2018, Shea was promoted to Chief of Detectives. Contrary to video allegations provided by
The New York Times, "Police Commissioner Dermot F. Shea has maintained that misconduct during the protests was confined to 'isolated cases' and that officers were confronted with violence by protesters." On January 1, 2022,
Keechant Sewell succeeded Shea as New York City's police commissioner, when
Eric Adams succeeded de Blasio as mayor. ==Dates of rank==