Jack Cassinetto spent the final day of his life doing what he loved most — capturing the beauty of California in his artwork.

Cassinetto died of a heart attack Thursday morning at his Sonora home after spending most of the previous day painting in his studio, as he did everyday. He was 73.

“He would come back for lunch or a coffee break and would generally have a painting in each hand,” said his wife, Connie Cassinetto, who had been with him for 35 years. “He would study his paintings to find the flaws in them and ask what I thought would make it better, then he would go back into his studio.”

“He did that seven days a week.”

Cassinetto was a prolific plein air artist known for his Tonalist-style work. He painted mostly Northern California landscapes, including Yosemite National Park, Lake Tahoe and the Gold Country.

Some of Cassinetto’s paintings are exhibited at New Masters Gallery in Carmel-by-the-Sea, Christopher Queen Galleries in Duncans Mills, and the Ventana Gallery in downtown Sonora.

“He liked beautiful things,” Connie Cassinetto said. “Just the beauty of the line, the form, the trees, the mountains, and the way all of those came together to create a piece of beauty that people would want to hang on their walls.”

Jack Cassinetto’s work has also been displayed in the pages of several art magazines and museums.

Connie Cassinetto, who is a photographer, said her husband’s affinity for painting started early in his childhood.

Jack Cassinetto graduated from Sonora High School in 1962, earned a bachelor’s degree in art and English from Sacramento State University in 1966 and a master’s degree in art from the University of Northern Colorado in 1972.

Jack Cassinetto was the descendent of Italian immigrants who moved to the county in 1905. He was the son of Ben and Mary Cassinetto, who preceded him in death. His mother was a Sardella, another one of the pioneering Italian families who came to the area in early 20th century.

After earning a bachelor’s degree, Jack Cassinetto moved back to Sonora and began teaching at his alma mater.

Jack Cassinetto, who has one son, Paul, from a previous marriage, met Connie in 1982 at the Josephine Room, a popular gathering spot that was located behind the Gunn House.

“I fell in love with him at first sight,” Connie Cassinetto said. “I didn’t have a choice at that point. He had big, brown eyes and wild, curly hair. He was honest, kind and obviously learned.”

At the time, Jack Cassinetto was running a real-estate company that he co-owned with his business partner and friend of 42 years, Mike Macon, of Sonora.

The pair ran the business together for about 10 years until 1988, when Jack Cassinetto went back into teaching at Dario Cassina High School in Sonora.

“He was absolutely made to work with those kids,” Macon said. “No matter how many times those kids had been told they were no good, when they got to Jack they knew he actually cared.”

Macon said they never said a cross word to one another throughout more than four decades of friendship. They spoke on the phone the day before Jack Cassinetto died because he didn’t show to the usual weekly morning coffee with a group of friends.

Connie Cassinetto said she woke up at 5 a.m. to find her husband dead on the couch. He was working through a cold the day before and responded to his wife when she called out to him about midnight to check on him from her room.

The coroner later said Jack Cassinetto had suffered a heart attack. His wife believes it may have been brought on by years of chemotherapy and radiation he had undergone since 2008 for treatment of right-tonsil cancer.

“It would have been better if he hadn’t been sick that night, but he was doing artwork,” Connie Cassinetto said. “That was really what mattered the most in his life — continuing to create artwork as long as he could.”

Jack Cassinetto was also close with his son, Paul, 49, who lives in San Mateo with his wife, Aileen.

Paul Cassinetto said his father instilled in him a respect for other people and the environment that he’s carried with him all of his life.

“He would see something in someone and really try to bring that out of them,” Paul Cassinetto said. “I remember as a kid if he found a hurt animal, he would take care of it until it was better and then let it go.”

Paul Cassinetto said his father also wanted to see the community grow, which was why he got involved in local politics.

Jack Cassinetto first served seven years on the Sonora Planning Commission before he was appointed to fill a vacancy on the Sonora City Council in 1985. He won re-election twice and served as mayor two times before retiring from public office in 1994.

An article in The Union Democrat from Jan. 20, 1994, quoted Jack Cassinetto reflecting on his tenure after he announced his plan not seek re-election.

"I've always been pro-development and pro-growth," he said. "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."

Jack Cassinetto is also survived by his brother, Ben, and sister, Marijane, who serves as the elected city clerk of Sonora.

A funeral service is scheduled for 1 p.m. Thursday at St. Patrick’s Catholic Church, 116 Bradford Street in Sonora, which will be followed by a private family burial graveside. A viewing will be held at Terzich and Wilson Funeral Home from 2 to 6 p.m. on Wednesday.

Contact Alex MacLean at amaclean@uniondemocrat.com or (209) 588-4530.