The son of a hero cop was promoted to detective on Thursday — and took the shield number of the officer who helped save his dad’s life.

Conor McDonald, son of NYPD Detective Steven McDonald, who was paralyzed from the neck down while on duty in a 1986 Central Park shooting, earned his gold detective shield bearing the number 97.

The proud dad watched on as Police Commissioner Bill Bratton promoted his son to detective.

McDonald’s shield number had been assigned to detective Brian Mulheren, who helped save his father’s life.

Bratton tweeted Thursday, “21yrs ago I had the honor to promote Steven McDonald to detective. Today I had the honor of promoting his son Conor.”