The son of a building contractor, van Sweden was raised in a large Dutch community in Grand Rapids, Michigan. He loved plants and gardening from an early age, and he honed his gardening and design skills in the small backyard of his family’s suburban bungalow. In 1960, at the age of 25, he earned a bachelor’s degree in architecture from the University of Michigan before studying landscape architecture at Delft University of Technology in the Netherlands. After three years, he returned to the United States and became a partner at Marcou, O'Leary and Associates. Then, in 1975, he founded the partnership with Wolfgang Oehme that would define his professional career and introduce the world to the New American Garden, an aesthetic that challenged conventional approaches to landscape design. Based in Washington, D.C., Oehme, van Sweden & Associates, now in its second generation (and known as OEHME, VAN SWEDEN | OvS), grew to encompass architecture, landscape architecture, and urban design, and completed many high-profile public projects in the nation’s capital and beyond.
Van Sweden promoted the firm’s ideas through lectures and books, including Bold Romantic Gardens (1990, coauthored with Wolfgang Oehme and Susan Rademacher), Gardening with Water (1995), Gardening with Nature (1997), Architecture in the Garden (2003), and The Artful Garden (2011). He was a Fellow of the American Society of Landscape Architects (ASLA) and among his many awards was the ASLA Design Medal in 2010. Van Sweden was honored by the Garden Writers Association of America, the American Horticultural Society, and other organizations.