Zeppa worked with the Obama White House, where the assignment was to connect Vice President Biden to the audiences for his policy agenda. She identified the validators a given group trusted and brought them in. One of those relationships became a friendship between Lady Gaga and the Vice President, which put him at the Oscars speaking on ending sexual assault and at the Final Four carrying the same message to college men. When the administration launched the Cancer Moonshot, she was on the team leading it. She convened the country's top cancer organizations and organized the inaugural Cancer Moonshot Summit.

She then ran the Creative Alliance as Executive Director. She grew the membership to include the leading production and advertising partners in the country and built partnerships with the major talent agencies. The work supported President Obama, First Lady Michelle Obama, then Vice President Biden, and Dr. Jill Biden after they left office.

She joined President Biden's presidential bid before launch as Chief of Staff and stayed through election day. She led the marketing team that built the logo and the campaign narrative. She served as Acting COO through the primary summer. As Digital Director she grew the fundraising team by more than 149%. In the general she was the campaign's liaison to the convention, worked on the creative team for content and writing, managed every speaker, and ran the digital after party.

At the U.S. Embassy in Mexico she worked across the issues the United States engaged on in the country, at a post of more than 30 agencies and 3,000 staff, the largest U.S. Mission in the world. She worked with senior officials in both governments on immigration, migration, and economic policy, and led the binational committee marking 200 years of diplomatic relations.

She served as Chief of Staff and interim CEO for Joe Kiani at Willow Laboratories, a 100-plus person medical technology company in diabetes and diabetes prevention. She ran a reorganization and relaunched the diabetes prevention app inside of ten months, working across electrical, mechanical, chemical, algorithm, and software engineering alongside clinical and marketing.