Gruppé was an American plein air landscape and seascape painter. His studio was in Gloucester MA. He is best known for his variety of impressionistic landscapes but also painted figures and portraits. From 1940–1970, he ran the Gloucester School of Painting at Rocky Neck, on Smith Cove in Gloucester, Massachusetts. His style was largely inherited from Monet. He also wrote books on brushwork, color, and oil painting techniques. His works have been sold by major auction houses such as Sotheby’s and Christie’s.