Catherine Ashton, the European Union’s first high representative for Foreign Affairs and Security Policy, transformed EU diplomacy with a pragmatic and understated approach. Known for her ability to foster consensus and navigate high-stakes negotiations, Ashton played a pivotal role in mediating the Iran nuclear agreement, the Kosovo–Serbia dialogue, and responding to global crises such as the Arab Spring and the Maidan Revolution. This chapter explores her negotiation philosophy, rooted in the question “and then what?”, which emphasizes long-term stability over short-term fixes. Ashton’s diplomatic style, marked by trust-building, process management, and persistence, provides valuable lessons for modern diplomacy. By prioritizing relationships, setting clear objectives, and ensuring buy-in from all parties, she demonstrated the power of quiet determination in achieving meaningful change.