Thum graduated from Claremont McKenna College in 1990 with a degree in Government. Following graduation, Thum moved to Berlin, Germany, after the fall of the Berlin Wall. Thum went on to earn an MBA from The Kellogg School of Management at Northwestern University.

In 2001, while working on a consulting project in South Africa for McKinsey & Company, Thum met people who lived in the townships and countryside who did not have access to safe water and adequate sanitation. These experiences inspired him to come up with the idea for Ethos Water. Thum led Ethos as President through its acquisition by Starbucks in 2005. From 2005 to 2008, he managed Ethos and other businesses as a vice President of Starbucks and guided its philanthropy as a Director of the Starbucks Foundation.

In 2008, Thum founded the not-for -profit organization Giving Water. Its mission is to fund programs providing water, adequate sanitation and hygiene education for children in need. Since then Giving Water has funded programs for over 6,000 school children in Kenya.

Thum cofounded and is CEO of Fonderie 47, a brand formed in 2009 to turn assault rifles into jewelry, watches and accessories, under the stated aim of reducing the number and impact of assault rifles and other small arms.

As of 2010, Thum lives in New York City's Greenwich Village, and is married to Actress Cara Buono.

In April 2012, the Tribeca Film Festival and the Disruptor Foundation awarded Thum the Disruptive Innovation Award.

In 2013, Thum launched Liberty United, an organization that partners with American communities and law enforcement to take illegal guns and bullet shell casings released from evidence and to create jewelry and other accessories in order to fund programs to reduce gun violence. The organization also provides children with extracurricular academic, Sports and art classes, as well as job training.

In October 2014, Thum was featured by Levi Strauss & Co. in its Unzipped series on innovators.

In September 2015, Thum was featured in the global advertising campaign for UBS and photographed by Annie Leibovitz.

In April 2017, Thum was received the For the Love of Children award from Children’s Home & Aid of Illinois.