Lambert auditioned for the ninth season of American Idol on August 25, 2009, in Dallas, Texas, at the encouragement of his mother, and earned a golden ticket to Hollywood Week.

On April 1, 2010, Lambert joined then-cast members Giglianne Braga, Justin Gaston, Ben Elliott, Kara Killmer and Amanda Phillips on If I Can Dream, a web reality series that followed aspiring artists as they pursued their dreams in Hollywood. His entrance was watched live by over a million internet viewers.

“I Didn’t Know,” a soulful pop song written by Lambert with Nasri Atweh and Adam Messinger, was selected and made into a music video by Clear Channel and 19 Entertainment, and then released on July 26, 2010, through iheartradio, then across the web. The video features Lambert playing at several Play Me I’m Yours piano art installations across the five boroughs of New York City, including prominent tourist locations such as the Brooklyn Bridge, Coney Island and Times Square. The 15th Annual Webby Awards selected Lambert’s “I Didn’t Know” music video as an Official Webby Honoree in the Online Film & Video: Best Editing category.

Lambert saw his first significant songwriting placements in 2012. On June 26, 2012, “Trouble,” a song co-written by Lambert and busbee was released as The X-Factor finalist Chris Rene’s second single. In September 2012, Lambert had his second studio album writing credit when his original song “What Makes You So Beautiful” (later shortened to “Beautiful”), co-written with Toby Gad, was included on Carly Rae Jepsen’s album Kiss.