Thomas, with Ed Clancy, Peter Kennaugh and Steven Burke, brought a packed Velodrome to their feet by breaking the record they had set in qualifying for yesterday's final.
They dominated their biggest rivals Australia, winning in a time of 3.51.659 minutes.
Cardiff-born Thomas was also part of the team that won gold in Beijing, as was Clancy, with Burke an individual bronze medallist four years ago and Kennaugh making his Games debut.
"The whole expectation and pressure around the team was massive this time around," said 26-year-old Thomas.
"All year we have been thinking about it and talking about the Aussies and the Kiwis, so to get on that track and deliver is a great feeling.
"We knew we could get another world record, we knew we were capable of it from our training.
"But it is one thing believing it and another actually doing it under all that pressure."
Burke, 24, added: "The final race just went so fast. Before I knew it I was into my last turn.
"I'm stunned to be honest. The first thing I felt when I went over the line was relief because I wanted it so badly."
- Steven Burke
- Peter Kennaugh
- Ed Clancy