- Played tight end for USC's football team and has two Rose Bowl rings. He was teammates with Junior Seau.
- Is a member of Sigma Chi.
- Appeared on a Men of USC calendar while attending the school.
- Modeled for Calvin Klein.
- Keeps in shape by lifting weights and doing various forms of martial arts, including jiu-jitsu and Krav Maga.
- Returned to the role of Austin Reed on Days of Our Lives in July of 2011 after a 16-year absence from the show.
- Sings for the rock band the Sleeping Masses.
- Has a comic-book collection.
- Shana Muldoon — Sister
- Deanna Muldoon — Mother
- William Patrick Muldoon II — Father
- University of Southern California, Los Angeles, CA
- Birth Name: William Patrick Muldoon III
- Birth Place: San Pedro, CA
- Profession: Actor