Cassinetto was born on March 26, 1944, in Sonora, California, to Ben and Mary Sardella Cassinetto, both scions of pioneering families from Genoa, Italy.[3][4] In 1966, he earned his BA in Art and English from California State University, Sacramento.[5] He earned a Master of Fine Arts from the University of Northern Colorado in 1972.[5]
As a young artist, he dabbled in sculpture, pottery, jewelry making and watercolor. He had painted all his adult life. His work was exclusively oil painting until 2008, and generally on boards. All work after 2008 is acrylic. His subjects were mostly Northern California landscapes from regions such as Lake Tahoe, Yosemite, the Northern California Coast, the American River, the Sacramento River, the Gold Country, and other locations in this area.[1][2][6][7][8][9]
Aside from being an artist, he had multiple occupations throughout his life, including that of being a commodities broker, a partner in the family business, a teacher, a Sonora City Councilman and Mayor of Sonora (1986-1994).[3] As Mayor, he had always been pro-development and pro-growth:
Maybe it's time for a change, to get someone from the other side. But I hope the people who plan on running will concentrate on more than one development here and one there and look at the big picture. Government is potholes, street lights and job descriptions. I hope they have an interest in the entire constituency.[3]
He was first married to Betty Jean Carter. Their only child, Paul, was born in 1968. Jack spent the last 35 years of his life with his second wife, Connie Sue Clark, a photographer. He died in his sleep on January 4, 2018.[10]