Castle, a Democrat, defeated Republican Alan Furey by a vote total of 548 to 394 in Tuesday’s election.
He will serve a term of four years.
The pair had been battling for the seat now occupied by Chris Mushett, who opted to run for an at-large seat.
Castle talked Tuesday after hearing the election results.
“One of the biggest influences in my life is a woman from New London who I spoke to this evening,” he said. “And, she told me that winning or losing this election isn’t a measure of my worth.
”I am looking forward to tackling some of the issues that have plagued this town in recent years, specifically the drug epidemic,“ Castle added.
Castle thanked the voters in the fourth ward for their support.
”I also want to shout out to Julie, my wife, for following me down yet another crazy path,“ he said.
Castle said he thought a lot about his dad Tuesday, who died 30 years ago.
”I’ve been wishing all day my dad were here,“ he said. ”Everything I’ve ever done in this life was to make him proud. I wish he were here.“
Furey had praise for Castle late Tuesday.
”Sure, obviously, I’m disappointed because I looked forward to serving the fourth ward on city council,“ Furey said. ”But, I knew when I signed up to do this Chris Castle was my opponent and I knew all he had done for the city with Imagine Norwalk and the NEDC (Norwalk Economic Development Corp.) I knew that defeating him was going to be an uphill battle.“
Furey said the fourth was going to win no matter who was elected.
”I’m passionate about the city of Norwalk and I can tell by what Chris does he is also passionate about making Norwalk a better place,“ Furey said. ”Either way, the fourth ward couldn’t lose.“
Furey was asked if he would consider running for office again.
”I wouldn’t rule it out at this time,“ he said.
The first, second and third wards were all uncontested races for four-year terms.
Deb Lucal will continue to serve the first ward, while Dave Wallace was elected to the second-ward seat and Samantha Ludwig remains the third-ward council member.
In January, Mushett will join Stephen Schumm, Steve Euton and Kelly Beck as at-large council members. In a race pitting five current council members vying for four seats, Erin Smetzer was the odd person out.