At age 14, Sobiech was diagnosed with osteosarcoma, a bone cancer which mostly strikes children. CBS reported that during his treatment he underwent 10 surgeries and 20 rounds of chemotherapy. He started writing music after his diagnosis.  In May 2012 his doctors informed him that he had up to a year to live. Sobiech recorded the song “Clouds” about his battle with cancer, and released it as a YouTube video in December 2012. It went viral, surpassing 3 million views at the time of his death. It currently has more than 10 million views and counting. Prior to his death, Zach Sobiech formed the band A Firm Handshake with friends Samantha “Sammy” Brown and Reed Redmond. A Firm Handshake’s first album, Fix Me Up, was released digitally in early 2013, charting in USA, UK and Canada. The debut single by A Firm Handshake is “How to Go to Confession” featuring Sammy Brown.

Sobiech died on May 20, 2013 of complications from osteosarcoma, at his home in Lakeland, an eastern suburb of Saint Paul, Minnesota, at age 18. His funeral was held at the Catholic Church of St. Michael and he was later buried in St. Michael’s Cemetery.  Rainn Wilson’s YouTube channel SoulPancake released a documentary about Sobiech, directed by director-actor Justin Baldoni, a part of its online reality series, My Last Days. The 22-minute episode of My Last Day: Meet Zach Sobiech has been watched more than 12 million times on the main SoulPancake YouTube channel.  Artists have released many tributes, including many cover versions of “Clouds” — with a prominent version of “Clouds” released on SoulPancake, featuring director Rainn Wilson himself, along with Bryan Cranston, Ashley Tisdale, Jason Mraz, Sara Bareilles, Colbie Caillat, Phillip Phillips, Passenger, The Lumineers, and many others. The music video on SoulPancake presented in collaboration with Wayfarer Entertainment was directed by Justin Baldoni, produced by Baldoni and Ahmed Kolacek, with Fouad Elgohari as associate producer and Nick Pezzillo as editor. The video has been viewed over 4.4 million times on the SoulPancake YouTube channel.  On December 5, 2013 a choir of 5,000 sang Sobiech’s hit song “Clouds” at the Mall of America. The event was organized by the KS95 Kids Radiothon in collaboration with the Children’s Cancer Research Fund and Gillette Children’s Specialty Healthcare.  Zach’s mother Laura Sobiech wrote a memoir about his life, Fly a Little Higher: How God Answered a Mom’s Small Prayer in a Big Way.