From then on and until he turned 24, Feist had already produced and written over 40 gold and platinum albums for artists all over Asia; primarily for the Japanese, Filipino and Malaysian markets.
Feist also wrote song for artists such as Kelly Rowland, Celine Dion, Mýa, John Legend, Jennifer Holliday, The Spice Girls, Shanice Wilson, Donnel Jones, Outkast, George Clinton, Aaron Carter, Kimberley Locke, Stacie Orrico, Brian McKnight, Jaya, Jesse Powell, and Regine Velasquez.
Feist produced, wrote, and arranged, "Come Together Now", a charity single made to benefit the victims of the 2004 Indian Ocean earthquake and tsunami and Hurricane Katrina in 2005.
In October 2005, Feist appeared on CNN's Larry King Live with Sharon Stone, Denise Rich and Sharpe to promote the release of the single.
In April 2013, Mark Feist co-wrote and produced "Lightning" and "More Than Just Friends" included as bonus tracks on American Ido alumni Jessica Sanchez's debut album Me, You & the Music as well as Warner's Artist Sabi's single "Cali Love" featuring Tyga.
Mark also spent a lot of time in the studio producing and writing with other artists such as Hot Chelle Rae, Candice Glover, Brit Smith and Sabi.