After moving to New York City to become a songwriter in 2009, Warner met Wade, a producer who had recently started his own label, WonderSound. Along with their collaboration, Warner also worked with the Yeah Yeah Yeahs, playing bass on their 2009 album, It's Blitz!, and designing a touring keyboard setup for the band. Wade and Warner released MNDR's debut single, "C.L.U.B.," in March 2009, and their first EP, E.P.E., arrived on WonderSound a year later. Also in 2010, Warner appeared on "Bang Bang Bang," the lead single from Mark Ronson's third album, Record Collection, and toured with him for a year. After signing to Ultra Records in 2011, MNDR released the Patty Hearst-inspired single "#1 in Heaven" and the debut album Feed Me Diamonds in 2012. That year, MNDR toured with Duran Duran, sparking a relationship that led to Wade remixing "Beautiful Clothes" by Duran Duran spinoff TV Mania in 2013 and Warner filling in for keyboardist Nick Rhodes during part of the band's U.S. tour for the Paper Gods album in 2016.

During this time, MNDR collaborated with many artists, including RAC and Kele on the 2013 single "Let Go," and Sweet Valley on their 2015 EP Dance 4 a Dollar. MNDR also appeared on Michna's 2015 track "Solid Gold" and on Flume's "Like Water" from his Grammy-winning album Skin, and worked with Jai Wolf, Charli XCX, and AlunaGeorge, among others. MNDR remained prolific in 2017, reuniting with RAC and collaborating with Martin Solveig and Oliver. That June, MNDR and Scissor Sisters released the single "SWERLK," which commemorated the one-year anniversary of the Pulse Nightclub Massacre and benefited the Contigo Fund, a Central Florida LGBTQ and Latinx organization. ~ Heather Phares, Rovi