Jem grew up in Groton, Massachusetts, a New England, apple-farming town northwest of Boston. She attended an all-girls day school, Nashoba Brooks, which, along with her mother's and father's innate feminism, provided the seeds of her entrepreneurial spirit. She founded her first business at age 11, a summer camp for local pre-schoolers. In 2000, after an INSEAD MBA and 5 years living in Germany, she moved to Tuscany and founded a 9-hectare boutique organic winery, Castello Poggiarello.
While managing the winemaking and sales for the estate, she worked as Italian portfolio manager for US wine importer North Berkeley, tasting thousands of samples a year, working in top cellars throughout Italy and France and traveling regularly in the US to promote wine. Since 2015, she has written a popular blog, The Truth About Tuscany, which provides a lighthearted take on life under the Tuscan sun. Today, in addition to running Fanciulle Vini, the winery she founded in 2019 with her sister, the writer Caitlin Macy, she consults with premier Tuscan estates on branding and strategy at JemMacyConsulting.com