Bjoerndalen, 40, edged ahead of former cross-country skier Bjorn Daehlie and moved alongside his compatriot as the all-time leading gold medallist with eight.
"It's a great feeling," the shy Bjoerndalen told a news conference, immediately adding: "But the Games are still underway.
"It's hard to realise what's happened. It will sink in a bit later."
Bjoerndalen, who also has 19 world championship titles to his name, won his first medal at the Nagano Games in 1998 and has claimed at least two medals at every Olympics since then. He also won the 10km sprint gold in Sochi.
Bjoerndalen, who started in the World Cup 20 years ago, was one of three members of the Norway relay to shoot clean in another dominant performance.
He had come close to winning his 13th medal in the 20km individual last week but had to settle for fourth.
He dropped out of contention in Tuesday's mass start when he made four mistakes in the final shooting.
There were no such mistakes on Wednesday.
"My shooting was really good, I was more focused than yesterday but today it was working again," he explained.
"I was really nervous before the race because you don't work for yourself only, but also for the team.
"I had not prepared myself for this it's a dream. Our performance is unique."
Compatriot Emil Hegle Svendsen, who skied the last leg to snatch his fourth Olympic gold, stressed the fact that he and his team mate owed Bjoerndalen most of their success.
"The (Norwegian) system has been built thanks to Ole's career. It's because of his extreme professionalism," he told a news conference.
"Ole is amazing - what else can I say," added Tora Berger, who started Wednesday's relay.
There is possibly still more to come for Bjoerndalen as he will be part of Saturday's relay, in which Norway will start as favourites, especially since they feel they have put ski issues behind them.
"What's changed the most is that we've got now some better skis," said Svendsen, who will probably not match Bjoerndalen's mark as he seems to aim for a shorter career.
"I want to quit earlier than him. I hope I won't get too greedy, maybe another four years," he said.
Czech Republic won silver in the mixed relay while Italy claimed the bronze.
France, who were among the favourites, dropped out of contention after Anais Bescond missed five of 10 targets in the second leg and finished a distant seventh.
In the mixed relay, two women race a 6km sprint and two men race a 7.5km sprint. They can reload up to three times per shooting session before having to complete a 150m penalty loop.
Berger was the first off the mark and despite two mistakes on the range, she passed the relay to Eckhoff in first position.
Eckhoff was a tad slow on the skis and trailed Czech Gabriela Soukalova by one second at the end of her leg.
The best of the Norwegians had yet to start, with Bjoerndalen and Svendsen, who one day earlier had claimed a dramatic mass start Olympic title.
Bjoerndalen's cross-country skiing abilities were too much to handle for Jaroslav Soukup, who finished 43 seconds off the pace.
Svendsen then just had to avoid a catastrophe on the shooting range, which he managed perfectly.
- Sports & Recreation
- Emil Hegle Svendsen