Sonoma County banking circles were shocked Tuesday by word of the unexpected death of Dave Brown, an admired and seasoned commercial-banking executive who worked for several local banks before joining Bank of Marin late in 2010.

Brown, 53, lay lifeless on the porch of his Santa Rosa home when his wife, Roni, arrived home shortly before 7 p.m. Monday. The couple's new dog, Ben, watched over him.

An autopsy will seek to determine the cause of the longtime Santa Rosa resident's death. Friends said Brown, an avid golfer, had seemed perfectly healthy except for mild symptoms of a cold.

"It's so shocking it's nearly impossible to say anything," said friend and colleague Debbie Meekins, president and chief executive of Santa Rosa-based First Community Bank.

"He was so young and so bright," Meekins said. "He was very successful in his career, very highly regarded in the banking community. The thought of it is almost unbearable."

Brown got his start in banking three decades ago with Bank of America in Sacramento. He worked for First Community Bank, North Valley Bank, Umpqua Bank and First National Bank of Nevada.

He was with Sonoma County's Exchange Bank for more than 17 years and was a senior vice president and real-estate loan administrator when he moved on in 2004.

"He played a significant role in our success during his tenure here," said Bill Reinking, chairman of Exchange Bank. "He was a good banker. We were good friends."

Brown was hired by Novato-based Bank of Marin in October 2010 and the following summer introduced the bank to Santa Rosa with the opening of a branch on Santa Rosa Avenue.

Russell Colombo, the Bank of Marin president and chief executive, said Brown's personal and business connections in Sonoma County and his decades in local banking were invaluable.

Colombo recalled meeting Brown two weeks ago at Charlie's, on the Windsor Golf Course.

"Dave knew half the people in the restaurant. Everybody knew Dave. It's impossible to replace that. And on top of that, he was a really nice guy."

Colombo said that throughout the offices and branches of Bank of Marin on Tuesday, employees received the news of Brown's death "in the same way, in stunned silence."

David Robert Brown was born March 3, 1959, in Redwood City and was only a few years old when his family moved to Santa Rosa. He graduated from Montgomery High in 1977 and went on to Sacramento State University, Santa Clara University and the Pacific Coast Banking School at the University of Washington.

Through the course of his career, he became a popular figure not only at bank branches but on golf courses and at community gatherings.

Said friend and business-banking client Rod Brownlee of Santa Rosa, "In a roomful of people, when Dave Brown was speaking, even though he was mostly a soft-spoken person, people would lean forward to make sure they could hear what he was saying."

On the links, Brownlee added, "He was a true gentleman -- and a much better golfer than I."

Brown served for a time as chairman of the Sonoma County Loan Consortium and a member of the board of Burbank Housing Development Corporation. At the time of his death, he was a director of Kid Street Learning Center.

His heartbroken wife, Roni, said, "He certainly enriched my life and I am so blessed to call him my best friend and husband.

"He lived every day with a smile on his face and made the best of what life threw at him."

Having blended her family with his when they married in 2002, Roni Brown said her husband loved her two daughters like his own and cherished being "Nonno" to grandkids George, Makenzie, Jackson and Alex.

Friend John Dennis, an officer of Northbay Biz Magazine, said it's hard to believe he enjoyed Brown's verve just last Thursday.

"We had a great conversation, as usual," Dennis said. "There's nothing you could say bad about the guy."

In addition to his wife and his grandchildren, Brown is survived by sons Thomas Brown of Santa Rosa; Matthew Brown of San Francisco and Patrick Brown of Chico; stepdaughters Megan Linsenmeyer of Rohnert Park and Lauren Graham of Elk Grove; mother Marian Brown of San Jose; father Robert Brown of Paso Robles; and sisters Winnie Brown of San Jose and Lenore Brown of Paso Robles.

Funeral arrangements will be made by Daniels Chapel of the Roses.

Brown's family suggests memorial donations to Kid Street Learning Center, 709 Davis St., Santa Rosa 95401, or to Schools Plus, P.O. Box 14714, Santa Rosa 95402.