Coyner sought his party's nomination for the same seat in 2012 but lost a primary to former school board member Sue Brand, who lost to Kupchick in the general election.
In announcing a new bid Monday, Coyner called for the state to stimulate the growth of 21st century jobs, greater efficiency in state government and fairer state taxes.
"I won't be content to just `represent' Fairfield," Coyner stated in a news release. "I want to actively build a better future for Fairfield and Connecticut. To me, this means having forward-looking ideas, actively working on these ideas and actually getting something done for Fairfield for a change."
A former bond trader in Tokyo and New York, Coyner left Wall Street to become a first responder. He is a full-time firefighter in Greenwich and a member of that town's Retirement Board.
Coyner said the state should focus on creating jobs in precision manufacturing, and in the health care, biomedical, green energy, exports, technology and tourism industries.
"We need new jobs that are more resilient to the boom and bust cycles that whipsaw our economy today," Coyner said in the release. "Our state, and our town of Fairfield specifically, needs to be seen as the preeminent place for new investment and growth."
He said a strong economy with wage growth would produces higher tax revenues, not higher tax rates and would allow the state to address economic inequality without unduly burdening any particular segment.
The candidate also called for more preventative health care and incentives to keep college Connecticut college graduate in the state.
Coyner holds an MBA in international business from George Washington University and a bachelor of arts in economics from Lewis & Clark College, according to the release. He was a bond and options trader for Morgan Stanley and Citibank for 14 years, stationed in New York and Tokyo. He has also worked as an aide in the U.S. Senate.
Coyner has competed in 11 triathlons, according to the release. He has said he left his finance career to become a first responder after his father collapsed and died just short of the finish line in a cycling and running race in California.
The candidate has been a Connecticut resident for 25 years and a Fairfield resident for five. His wife, Natalia is a registered nurse at St. Vincent's Medical Center in Bridgeport and doctoral candidate at Fairfield University. They have two grown children.
When he sought the Democratic nomination in the 132nd District two years ago, Coyner lost the party-caucus endorsement by a single vote. In the subsequent primary, however, Brand got 69 percent of the vote to Coyner's 31 percent.