Leonard Joseph Cariou OC OM (born September 30, 1939) is a Canadian actor, best known for his portrayal of Sweeney Todd in the original cast of Sweeney Todd: The Demon Barber of Fleet Street, for which he won the Tony Award for Best Actor in a Musical, and for playing the patriarch Henry Reagan, NYPD Police Commissioner (retired), in the multi-generational television series Blue Bloods on CBS.

He appeared in two episodes of the revival series from 1995 to 2000:

• "Corner of the Eye" - Father Anton Jonascu
• "Seeds of Destruction" - Doc Wells

Archive footage of his first appearance was later used in the clip show "The Voice of Reason".