He began his career as a child actor, receiving recognition for his role as Albert Tranelli in the TNT comedy-drama series Men of a Certain Age (2009–2011).

He has made guest appearances in several television series such as, Criminal Minds, ER, House, Grey's Anatomy and Amazon Prime Video's The Romanoffs.

[6] During middle school, he joined the band The Feaver with his friends and future Wallows members, Cole Preston and Dylan Minnette.

[7] After appearing in a McDonald’s commercial that aired during the Super Bowl, Lemasters began his acting career at the age of 9, playing the role of Frankie in an episode of Six Feet Under in 2005.

In April 2007, he appeared as Jacob Marshall-LaHaye in the Christian drama television film Love's Unending Legacy, for which he earned his first Young Artist Award nomination.

The band began releasing songs independently in April 2017 starting with "Pleaser", which reached number two on the Spotify Global Viral 50 chart.

In 2018, Wallows signed a deal with Atlantic Records and released their major label debut EP, Spring, including singles "Pictures of Girls" and "These Days".