Yeh was born in Glenview, Illinois to clarinetist parents John Bruce Yeh and Jody Yeh. She has an older sister, Jenna, who is a chef; as well as a younger half sister, Mia. Yeh grew up in the suburbs of Chicago before moving to New York City to attend Juilliard for percussion. She kept journals from a young age which turned into her blog in 2009.

Yeh is of Chinese and Jewish descent. Yeh was raised in Glenview, Illinois, and attended Glenbrook South High School and the Midwest Young Artists Conservatory, where she was a member of two percussion ensembles—The Rattan Trio and Beat 3– which won consecutive gold medals (2004 and 2005) in the junior division of the Fischoff National Chamber Music Competition. Yeh moved to Brooklyn and attended the Juilliard School, where she was editorial assistant and writer at The Juilliard Journal and in 2011 earned a Bachelor of Music degree in percussion. Yeh married fellow Juilliard music major Nick Hagen in 2015 and moved to the Minnesota-North Dakota region where Hagen is a fifth-generation farmer.

In October 2016, Yeh published her first book, Molly on the Range: Recipes and Stories from An Unlikely Life on a Farm (Rodale Books), for which she won the Judges’ Choice IACP Cookbook Award in 2017. In June 2018, it was announced that Yeh would be hosting a cooking show on Food Network. The series, Girl Meets Farm, debuted on June 24, 2018.

In November 2018, Yeh announced that she and her husband were expecting their first child. On March 30, 2019, Yeh gave birth to a daughter, Bernadette Rosemary Yeh Hagen, named after her husband’s great-great-grandfather Bernt (who started the Hagen farm) and her own great-great grandfather, Bernard.

Also in November 2018, she was a co-host on From the Top, a podcast showcasing young classical musicians. Yeh had previously appeared on the show twice as a teenager, in 2004 and 2007.