Vack was born in the West Village neighborhood of Manhattan in New York City[2] to Jane (née Spivack) and Ronald Brown, a movie producer and writer.

[7] Vack has guest-starred in single episodes of Hope & Faith (2004), Third Watch (2004), Law & Order: Special Victims Unit (2005), Ghost Whisperer (2009) and Cold Case (2010).

He also played a lead acting role in a music video for the song, 'Love in the Old Days', by James Franco's and Tim O'Keefe's band, Daddy.

[6] He co-starred as Alex Merriweather in the Amazon Video comedy-drama series Mozart in the Jungle (2014–2015), alongside Lola Kirke, Malcolm McDowell and Bernadette Peters.

[8] In 2024, Vack released "www.RachelOrmont.com" a feature film he wrote and directed; described as a "technosatire about growing up in captivity" starring Betsey Brown, Chloe Cherry, and Dasha Nekrasova.