[1] Kastner has written and produced music for Tkay Maidza, Espa,[2] Kiah Victoria and others in collaboration with songwriter Autumn Rowe.
[4] Kastner is a Founding Partner & Creative Director of the Milt Olin Foundation, launching a global movement dedicated to ending distracted driving through the Stop Wrex campaign.
[8] Previously, Kastner was CEO of FanRocket, an internet digital content production company he founded in 2005.
[9] He produced and directed video for numerous online projects and networks including Wonderglen for HBO,[10] Casual Fridays and HSN's, "Faces of Beautiful You.
[15] After being "fired" by Donald Trump, Kastner, who holds a master's degree in music composition from Boston University, wrote songs about his experience on the show.