Paulo Costanzo was born on September 21, 1978, in Toronto, Ontario, Canada. Growing up in Brampton, a suburb of Toronto, he was influenced by his Italian father and Jewish mother's cultural backgrounds. He attended Mayfield Secondary School for the Arts, where he developed his passion for the performing arts. After completing one year at Ryerson University's theater program, he dropped out to pursue television and film roles in Toronto.
Costanzo's early career took off with his role in the Barbra Streisand-produced film Rescuers: Stories of Courage: Two Couples (1998),where he played a Jewish teen hiding from the Nazis in 1939 Belgium. He then landed the recurring role of Aximili-Esgarrouth-Isthil on Nickelodeon's Animorphs (1998),which ran for two seasons.
In his early twenties, Costanzo attended an international cattle call audition for an unnamed Dreamworks film. A week later, he received a call from his agent, informing him that Todd Phillips wanted him to screen test for Road Trip (2000) after seeing his tape. This marked the beginning of his professional career in the United States, as he was offered the role of Rubin Carver.
Throughout his career, Costanzo has played major supporting roles in several films, including Josie and the Pussycats (2001) and 40 Days and 40 Nights (2002),and starred opposite Woody Harrelson and Alicia Silverstone in Scorched (2003). He also had a recurring role on the Friends (1994) spin-off, Joey (2004),alongside Matt LeBlanc.
In the mid-2000s, Costanzo headlined Douglas Coupland's Everything's Gone Green (2006),a festival darling that won numerous awards. He then starred in the cult horror hit, Splinter (2008),which won six Scream Awards, including best picture. He also appeared in A Beginner's Guide to Endings (2010),alongside J.K. Simmons, Scott Caan, and Harvey Keitel.
From 2009 to 2015, Costanzo starred as Evan R. Lawson on the USA network's Royal Pains (2009) for its eight seasons, directing three episodes. In 2015, he recurred as Shed Garvey on Syfy's The Expanse (2015),and played the critical role of Ray Halle in four episodes of HBO's Emmy-winning drama The Night Of (2016). He then starred opposite Marisa Tomei and Minnie Driver in the high-concept short film Laboratory Conditions (2017) and appeared as Lyor Boone, chief political advisor to the President, opposite Kiefer Sutherland on ABC's hit show Designated Survivor (2016).
