Bolt, who gave himself the title after defending the 100 and 200 crowns he won in Beijing four years ago, anchored the Jamaican quartet of Nesta Carter, Michael Frater and Yohan Blake to victory in 36.84 seconds, knocking 0.2 off the record they set at last year's world championships.
The win gave Bolt his sixth career Olympic gold from two Games and the 25-year-old, usually so assured, was wary of promising a three-peat.
"I've thought about it but I think it is going to be very hard. Yohan is coming through and I'm sure a lot of the other young guys are coming up so I will see what happens in four years," Bolt said.
"It's always a beautiful feeling to end off like this. We did it last year in the world championships - for me it's a wonderful feeling," Bolt said.
"The team came out and gave their all. I knew a world record was possible."
The United States team of Trell Kimmons, individual bronze medallist Justin Gatlin, Tyson Gay and Ryan Bailey won silver in 37.04 to equal the old record.
Canada finished third but were disqualified for a lane infringement, leaving the athletes in tears on the track as Trinidad and Tobago were awarded the bronze in 38.12.
US lead-off man Kimmons got a flying start and the Americans appeared to have the edge but by the third leg Jamaica's 100 and 200 silver medallist Blake came off the bend level with rival Tyson Gay and once Bolt got the baton there was only ever going to be one winner.
To a tumultuous noise, Bolt pulled away from American Ryan Bailey and, for once, there was no showboating as he kept going all the way to the finish even dipping for the line.
"I was really running hard. I was really focused on running as fast as possible because we really wanted the record but I smiled a lot after the race," Bolt told a news conference.
"I did do a little pose after the race so it was okay and the fans really appreciated the world record so they'll forgive me for that," he said of his lack of posturing.
"Without the US, we would be nobody, and the US without Jamaica would be nobody,. We challenge each other back and forth, every season."
Bolt wanted to keep the baton but track officials would not let him, resulting in boos from the 80-000 strong crowd, however the athlete said he did get it back.
"I got the baton back but at the start he was saying I couldn't keep it because it's the rule.
"It was kind of weird because he actually told me that if I didn't give it back I would be disqualified so I just gave it back to him," Bolt said to laughter.
The crowd had already worked themselves up into a frenzy after watching home favourite Mo Farah win the 5,000 to complete a distance double, and the relay, the final event of the stadium's track and field programme, took place in an atmosphere more akin to a rock concert.
The Jamaicans then went on a lap of honour, high-fiving and kissing members of the crowd and after the medal ceremony, spectators were demanding an encore from their idol chanting "we want Bolt".
He obliged by orchestrating the crowds' cheering before swapping poses with Farah - doing the Britain's 'Mobot' while the distance runner pulled the 'lightning bolt'.
It was the first time in four global championships that the US men had successfully got the baton round after fluffing changeovers in Beijing four years ago and the last two world championships.
The silver also provided consolation for Gay who is the second-fastest man ever over 100 but had never won an Olympic medal and had been in tears a week ago after finishing fourth in the individual event.
"It feels good. Last week was very emotional for me," he said.
"I was very upset. Me getting it tonight is just a blessing and it fills that spot in my heart."
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