Born and raised in New Jersey, 30 minutes from New York City, Ostergaard was exposed to the world of art at an early age. His father, a professional commercial and industrial photographer gave him his first art lessons. Trips to NY museums and galleries stimulated his visual imagination and convinced him this was his world. He studied painting and art history at Montclair State University.
After a four month graduate internship he was asked to remain on staff at the Museum of Contemporary Crafts in New York, now the Museum of Arts & Design. A year later, Glenn met the American dancer Martha Graham and became her personal assistant; an association that had a lasting impact on his approach to art. At Miss Graham's suggestion, Ostergaard began experimenting with three-dimensional forms which soon lead to the development of his signature pillow sculptures.
Ostergaard left New York in 1977, and after receiving encouragement from Betty Parsons, spent the next five years perfecting his pillow sculptures. He returned to painting in 1980 creating large, lyrical and colorful canvases. Once again, Ostergaard was enjoying the physicality of painting and in love with color.
Since 1990, Ostergaard has lived in the Palm Springs, CA area and has traveled extensively, continuing to develop his expressive vocabulary in his unique paintings and sculpture. Glenn and his husband David, are founding benefactors of the Kaplan-Ostergaard Glass Center at the Palm Springs Art Museum, where they have curated exhibits from both their extensive glass collection and works from outside their collection.