John began writing music at the age of 12. His first band, Family Crisis, played shows with 7 Seconds and Bad Religion. In 1994 he formed Goldfinger as lead singer, songwriter, producer, and mixer. Known for dynamic live performances, Goldfinger played 385 shows in 1996 alone. Goldfinger has sold 4 million albums worldwide. During his time as an A&R for Red Bull, Maverick & Warner Bros. Records, Feldmann signed The Used, D.R.U.G.S, Goldfinger, Showoff, City Sleeps, Story of the Year, Foxy Shazam, Mest, Itch, Blitz Kids and Beartooth. John is currently A&R for Big Noise. John has also done production work/songwriting for The Cab, The Veronicas, Krewella, All Time Low, Sleeping With Sirens, Sweet Suspense. Avicii, Good Charlotte, Mest, The Used, Story of the Year, Ashlee Simpson, One Ok Rock, Hilary Duff, Goldfinger, Showoff, The Matches, Atreyu, City Sleeps, Anthony Green, Oh Honey, Beat Union, Cute Is What We Aim For, Escape the Fate, Get Scared, After Midnight Project, Foxy Shazam, Allstar Weekend, Panic! at the Disco, Boys Like Girls, Megan Joy, Jessica Lowndes, Plain White T's, 5 Seconds of Summer, Mandy Moore and Kelis among others. Most recently he produced the seventh studio album for Blink 182 titled "California" which landed both he and the band their first Grammy nomination for "Best Rock Album". John has also been nominated for a Grammy for Best Rock Performance for his work with Fever 333 on Made An America. Also in July of 2017 John was awarded the "Influencer" Award at the Alt Press Music Awards (APMAs).