- Sang in a church choir and at weddings as a boy soprano.
- Made his stage debut in the chorus of a Canadian production of Damn Yankees in 1959.
- Starred alongside Angela Lansbury in the original 1979 Broadway production of Sweeney Todd; the pair teamed up again when Cariou landed a recurring role as a spy on Lansbury's series Murder, She Wrote.
- Narrated the Oscar-winning 1989 documentary short film The Johnstown Flood.
- Elected into the American Theatre Hall of Fame in 2004.
- Featured as corrupt billionaire Louis Tobin in season three of Damages.
- 1970, Tony — Actor (Musical): Nominee
- 1979, Tony — Actor (Musical): Winner
- 1973, Tony — Actor (Musical): Nominee
- 2009, Emmy — Outstanding Supporting Actor in a Miniseries or a Movie: Nominee
- Laurel Cariou Freedy — Daughter
- George Marius Cariou — Father
- Heather Summerhayes Cariou — Wife
- Lauren Bacall — Ex-significant Other
- Glenn Close — Ex-significant Other
- Susan Kapilow — Ex-wife
- Patricia Otter — Ex-wife
- Molly Estelle Cariou — Mother
- University of Manitoba, St. Paul's College, Winnipeg, Manitoba, Canada
Season 4, Episode 10
- Birth Name: Leonard Joseph Cariou
- Birth Place: Winnipeg, Manitoba, Canada
- Birthday: September 30, 1939, Libra
- Profession: Actor