Horvitz & Levy’s Agatha Mouillet Has Learned to Thrive on Change

To make a name for yourself in the world of marketing and business development, you have to be flexible. No matter the client or the project, success depends more on your ability to plan strategically, chart the business landscape, and follow it all through.

This is why Agatha Mouillet, the new business development manager at Horvitz & Levy, California’s top appellate law firm, has been able to thrive in her new position. Her journey has been shaped by a constant interplay of challenge, adaptation and growth. She’s worked across continents, industries, and disciplines, and as a result of her versatility and resilience, she has been able to hone her skill set in exceptionally diverse areas. 

“Each sector has demanded that I learn new regulatory environments, client expectations, and competitive landscapes,” says Agatha. “Given the wide range of business models and cross-cultural settings, I had to develop rapid learning methodologies and adaptable strategic frameworks.”

At Home in LA

Since February, Agatha has been the business development manager of Horvitz & Levy, a leading Californian appellate firm noted for its extensive experience in civil appellate litigation, which has enjoyed a high success rate before the California Supreme Court and the Ninth Circuit Court of Appeals.

Agatha’s task has been to lead strategic business development initiatives at Horvitz & Levy, helping the firm to raise its visibility, grow its client base, and boost revenues in key legal sectors, which the firm has designated as healthcare, insurance, entertainment and Fortune 500 companies. 

To do this, Agatha has established business development plans for each attorney. She has also created new marketing and social media strategies for Horvitz & Levy, including a redesign of its website. Agatha is also helping to implement a new customer research management system to track and increase business development. The firm’s client list includes many Fortune 500 companies, including major players in energy, entertainment, healthcare, and insurance.

In her work at Horvitz & Levy, Agatha has worked to raise the profile of individual attorneys. Two female attorneys, Shane McKenzie and Lisa Perrochet, were named Top Women Lawyers in the Daily Journal. She also helped organize the award ceremony for attorney David Ettinger when he was inducted into the California Lawyers Association’s Appellate Lawyer Hall of Fame this year. As a result of her efforts, Agatha was named by her firm as a nominee for Best Professional Initiative in the American Lawyer Industry Awards. The award ceremony will take place on Wall Street in New York in November.

Mastering Diversification

While Agatha’s ability to execute on behalf of her law firm might sound impressive, her track record is even more extensive, having done similar work at the University of Birmingham in the UK where she served as a project manager. Agatha worked with the university’s Atom Interferometry Group, which specializes in quantum sensing technologies, applying them in research and practical applications across many sectors.

During her time at the University of Birmingham, Agatha managed 10 advanced scientific quantum physics projects worth up to $6 million. She also managed operations for a 20-member interdisciplinary team developing cutting-edge quantum sensing technology to detect and monitor subsurface activity—a field at the frontier of defense, infrastructure, and space applications. In addition to managing the financial and operational aspects of the Group, she helped to better market and increase its visibility, and coordinated with partners such as the UK Ministry of Defence and BAE Systems

Interestingly, Agatha leveraged skills at the University of Birmingham that she had picked up in earlier work as a product manager and marketing director for Kos Lighting in Paris, and at Decathlon, also in Paris, where she was an event manager.

“I have managed multiple major relocations across different business cultures,” she remarks, “and each one required complete professional reinvention.” Agatha acknowledges that this has made her culturally fluent. She is able to work with clients in English, French, and Spanish. After moving to California, Agatha also worked at Alliance Française, providing expert instruction in French language and culture, and served as a brand ambassador for 321 Acting Studio, a renowned school dedicated to training aspiring actors, helping to launch the careers of many students.

Everything is Possible

Agatha’s journey is far from over. She aspires to become a globally recognized leader in strategic business development, someone who in her words not only drives growth for high-impact organizations, but also works to shape best practices across industries through thought leadership, innovation, and mentorship.

She hopes to consult international firms as they enter or expand with US and EU markets, offering strategies that integrate cross-cultural intelligence with data-driven growth models.

She also hopes to contribute to policy and educational initiatives that promote global business literacy and support underrepresented talent, particularly women, in traditionally male-dominated sectors, and to publish and speak regularly at industry conferences on modern business development, cross-cultural negotiation, and innovation in legacy industries, such as law, science, and manufacturing. 

“I believe that curiosity, adaptability, and integrity are the most powerful drivers of long-term impact,” says Agatha. “Ultimately, my goal is not just to achieve personal success but to build platforms and systems that help others grow alongside me.”