A founding member of The Mars Volta, she has been a studio and touring musician in bands for Cher, Gwen Stefani, P!NK, Veruca Salt and Tegan and Sara.

In 2011, Gardner formed Telstar with Chris Unck of Butch Walker and the Black Widows, recorded Hot Knives EP and the two singles "Getting Around Town" and "Lightning's Girl", plus released music videos for "Are You Hungry" and "everysinglebodyelse".

As a returning member of Pink's band, Gardner began promotional appearances in support of The Truth About Love, with a September 2012 album release date.

While on a break in the middle of Pink's The Truth About Love Tour, Gardner joined Moby's band for performances on Conan, plus three live shows at The Fonda Theatre in Los Angeles on October 3–5, 2013.

[5] In early 2017, she joined the Classic Cher residency show with dates in Las Vegas and Washington, D.C. From 2017 to 2019, Gardner was Pink's live bassist on the Beautiful Trauma World Tour.