In 2006, Lawson began a starring role in the Australian soap opera Neighbours as Frazer Yeats. His role earned him a nomination for Most Popular New Male Talent at the 2007 Logie Awards. His character Yeats left in April 2008.
Lawson had a small role in the 2011 film No Strings Attached, which starred Natalie Portman and Ashton Kutcher. In August 2012, he landed a recurring role in the ABC sitcom Don't Trust the B---- in Apartment 23 as Benjamin, a love interest for main character Chloe (Krysten Ritter).
In August 2017, Lawson was cast as Rick on the second season of the Netflix original series, 13 Reasons Why.