Having worked as an uncredited extra on television shows including Beverly Hills, 90210[2] and Dr. Quinn, Medicine Woman,[3] Lafferty received his first significant acting role in a school play when he was 10 years old.

In 1997, at age 12, Lafferty made his small-screen acting debut with a voice-over role in the made-for-television film Annabelle's Wish.

In 2002, Lafferty starred in the ESPN made-for-television film A Season on the Brink, an adaptation of the book of the same name by John Feinstein.

In 2003, Lafferty was cast in his breakout role of Nathan Scott on The WB/The CW teen drama series One Tree Hill.

In May 2011, The CW renewed the series for a ninth and final season, for which Lafferty chose to return on a recurring basis rather than in a full-time starring role.

[13] He began dating Australian actress Alexandra Park in 2015 after meeting on the set of The Royals, when Lafferty directed several episodes.