The Hennessey Communication team has worked with clients such as:

• City of Bainbridge Island
• Judith Billings for Superintendent of Public Instruction
• Boreal Songbird Initiative
• U.S. Bureau of Land Management
• Central Puget Sound Council of Camp Fire
• Children’s Hospital and Regional Medical Center
• Citizens for a Vashon Public Hospital District
• Communities Connect Network
• Corporate Psychology Resources
• DAWN -- Domestic Abuse Women's Network
• Discovery Channel Website
• Evergreen Funding Consultants
• Evergreen Hospital
• U.S. Fish and Wildlife Service
• Fred Hutchinson
• Hart Crowser
• Humanities Washington
• Institute for Environmental Research and Education
• International Academy of Design and Technology
• International Association of Conference Centers
• Lifelong AIDS Alliance
• National Marine Fisheries Service (NOAA)
• Office of the Premier of Canada
• Pierce County AIDS Foundation
• Redwood Forest Foundation
• Seattle Academy of Arts and Sciences
• Seattle Pride Festivities, 2005 and 2006
• Seattle Public Utilities 2004 and 2005 Drinking Water Reports
• Seattle Public Utilities 2007 Water System Plan
• Social Enterprise Group
• Starbucks
• Treehouse
• Triangle Associates
• U.S. Tennis Association/Northwest Chapter
• Women and Girls Foundation of Southwest Pennsylvania
• YMCA of Greater Seattle