At Studio William Hefner, we have developed a practice that fully integrates architecture, landscape, and interiors into a holistic design experience.


Our Philosophy

Our diverse portfolio is distinguished by modern and traditional as well as regionally specific architecture. All of our projects share a spirit of warm livability with a luxury of details and materials.

Our approach to design centers on our clients. We listen for their dreams as well as their practical requirements. We observe; we talk; we study; we test ideas and options. Our work begins with how the client will actually use a space, designing from the inside out. Our process builds on that vision, to create environments that will enrich life in intuitive and meaningful ways.

Our People

Our team is a family, built on the strength of deep collaborative relationships that help us respond creatively to our clients and partners. From our architects and designers to all of our studio members, we work together to provide seamless service across
the life of a project.

Our Practice

For over three decades Studio William Hefner has created luxury homes in California, across the US, and internationally.

With offices in Los Angeles and Montecito, our projects range from new urban houses to country estates and landmark restorations, as well as commercial typologies. We achieve the fullest experience of a space for our clients when we can tailor interior design and custom furnishings to the character of the architecture and landscape.

Our work is always guided by a quest for simplicity and elegance. We are grounded in an appreciation for the fine craft of building and a harmonious use of natural forms and materials.

Balance is a central condition of our practice. Everything we make emphasizes authenticity and historical reference, while embracing 21st century technology, comforts, and spatial invention. We seek a modern lightness in all that we do, to create places that are warm and understated, evocative and original, and always, richly restful.

  • about3

William Hefner

William Hefner is a fifth-generation Californian and the founder of the architecture and design firm Studio William Hefner. Established in 1989 in Los Angeles, the practice encompasses new and restoration architecture, interior and furniture design, and landscape architecture and design, with a focus on luxury homes for modern living. Known for his versatility in both traditional and modernist architecture, William has created landmark estates in a range of styles that share a devotion to craft and detail. His interest in environmental building has led to the application of sustainable practices throughout his portfolio. His work has been widely published in design books and magazines in the United States and abroad. William is the author of three books, California Homes, California Homes II, and Chateau des Fleurs. He lives in Los Angeles and Montecito with his son, Koji.

Carla Vaga

Carla Vaga joined Studio William Hefner in 1998 after earning a Bachelor of Architecture degree from California State Polytechnic University in Pomona. Her training in classical architecture included a year of study abroad in Florence, Italy, and Athens. Carla received AIA certification in 2009. She was made Principal in the firm in 2013 and Partner in 2021. Carla has extensive experience leading multiple residential and commercial projects in a wide variety of styles, as well as working on multi-family and mixed use buildings. She has special expertise in the design, craft, and execution of all interior architecture typologies. Carla is LEED accredited and guides the firm’s handling of LEED certified commissions and sustainable design. She incorporates green building design practices into all projects.

Nathalie Aragno

Nathalie joined Studio William Hefner in 2000 and became an Associate in 2005. She was named a Principal in the firm in 2013 and was made Partner in 2021. A native of France, Nathalie earned her master’s degree in Architecture from the prestigious French School of Architecture, Paris-la-Seine. Her prior work experience includes the Paris office of architect Santiago Calatrava and the New York office of BNK Architects. At Studio William Hefner, she leads a range of residential projects, focusing on end-to-end service in the design and construction of custom homes. Her social vision has guided the studio’s pro-bono work, winning design competitions most notably in 2009 and 2010 from Habitat for Humanity of Greater L.A., in the affordable housing and multi-family home categories.

Michael Aquino

Michael Aquino joined Studio William Hefner in 2004 after graduating from Otis College of Art & Design with a BFA in Architecture, Landscape, and Interiors. While at school, he was the recipient of the Sally Sirkin Lewis travel scholarship to study architecture in Europe. An Associate at the firm since 2013, Michael and his team work alongside William on the design of family residences, with a particular emphasis on developing interior architecture details for all home typologies. Michael was part of the studio’s award-winning teams in the 2009 and 2010 design competitions for Habitat for Humanity of Greater L.A, in the affordable housing and multi-family home categories.

Mark Imagawa

Mark Imagawa became an Associate at Studio William Hefner in 2013. Trained in structural engineering at the University of California Irvine, he received advanced certification in project management from UCLA in 2005, and joined the firm that same year. Mark is a LEED certified professional with a credential in Building Design & Construction, demonstrating the ability to implement green technology in all phases of a project. He is a leader in adopting modern technologies for the studio, applying new building concepts, materials, and methods in order to solve ever more complex technical visions for highly detailed projects.

Bob Irvine

Bob Irvine has collaborated with William since 2009 and now directs the Montecito office of Studio William Hefner. He focuses on prospective property development as well as the construction of new luxury homes for the Santa Barbara region. Bob is trained in landscape architecture and planning, and he leads the Landscape practice for the firm. He studied at the University of Oregon and began his professional career with posts at Skidmore, Owings & Merrill and at HOK in San Francisco. He has over thirty years of multidisciplinary experience in all phases of development and planning for significant
residential estates, including securing public entitlements, construction management, and owner’s representation. He brings to the firm comprehensive expertise in the planning and practice management of projects of all sizes.