Glenn Tunstull was born in New York City in 1950, and has said that he always knew he was going to be an artist. His early interest in drawing was supported by his family, while growing up in Detroit, where he and his family moved to in 1958. After concentrating in commercial art at Cass Technical High School, he studied at Parsons School of Design in New York for two years.

He left school to work for a number of pattern companies before creating fashion illustrations for Women's Wear Daily and Vogue Magazine. In 1975, Tunstull moved to Europe, and based in Paris and Milan, produced fashion illustrations for design houses including Hemes and Kenzo, and publications such as Marie Claire and Votre Beaute. Upon returning to New York in 1977, the artist worked for many editorial, retail, and beauty clients including The New York Times, Calvin Klein, Polo/Ralph Lauren, Bloomingdales, Neiman Marcus, Revlon, and Clairol. In 1997, Tunstull created illustrations for a children's book published by Simon and Schuster. He has taught at Parsons School of Design, and Pratt Institute.

A period of global travel, beginning in 1996, would prove to be a turning point in Tunstull's artistic development. Starting with a trip to France, he would create off-the-cuff documentary watercolors that faithfully recorded the scenes he was experiencing. Subsequent visits to Jamaica, Brazil, Australia, Martha's Vineyard, and other locations would prove to be equally inspiring. Tunstull was particularly drawn to sites that combined water and sky, and the play of color. In 2000, he began painting in oil, creating expansive landscapes and seascapes based on close observation. As the work developed, a sense of abstraction emerged, while the desire to represent reality remained strongly present.

Tunstull has acknowledged the influence of a number of painters, including van Gogh, with his intensity of color, Hopper and his play of light on the landscape, Klimt, particularly his densely detailed scenes of nature. The latter's sense of all-over abstraction relates to a series of paintings that Tunstull developed while working in Brazil. These vibrantly colored abstractions composed of block-like pixels would provide the model for the artist's newest work. These abstracted beach scenes and landscapes present a sparkling vision of some of his favorite subjects, including the skies and waters of Martha's Vineyard and Bahia, Brazil.

Tunstull has exhibited his work in many solo exhibitions including those at the Picture That Gallery in Stamford, CT and the Cousin Rose Gallery in Martha's Vineyard. The artist's work is in numerous private collections. Since 2003, he has lived and worked in Claverack, NY.