Sweden took silver and finished two seconds behind, after fantastic legs by Charlotte Kalla, Ebba Andersson and Stina Nilsson, while Olympic Athlete from Russia came third to take the bronze, 43.3 seconds behind the winners.
Norway missed out on a medal four years ago at Sochi 2014 and looked to be struggling again in the first two legs in PyeongChang. However, Ragnhild Haga, who won gold in the women's 10km free, managed to close the gap to 3.4 seconds in the third leg before she handed over to Bjoergen, with Sweden in the lead, and 0.3 seconds ahead of OAR.
The 37-year-old Bjoergen accelerated up the first hill with Nilsson snapping at her heels at the front of the field, but Olympic sprint champion Nilsson had no answer, and Bjoergen rounded the final corner and sped over the line for victory.
The 37-year-old Bjoergen has now won three medals at PyeongChang 2018 after landing silver in the women's 15km pursuit and bronze in the women's 10km freestyle, and eight gold medals in total. Nilsson added a silver to the gold she won in the women's sprint classic.
Bjoergen knew she faced a tough final leg against Nilsson. "The other girls gave me a good position, but I had to try and push hard all the way," she said. "I knew I could do it if I had a good day. I thought it was going to be hard when I had Stina (Nilsson) on my skis on the last lap so I'm very happy."
Haga said that she had to be patient during the third leg. "I was focused on hunting the others in front of me," she said. "It was really fun to catch them – almost catch them – and send Marit (Bjoergen) out there. I was thinking Stina (Milsson) was going to be strong in the finish but Marit (Bjoergen) had just enough metres and she was sprinting faster, so I was happy that Marit managed to cross the line first."
Norwegian team-mates Oestberg and Jacobsen were both excited to win gold after what they felt had been tough first and second legs respectively.
"I was the first one out and my plan was to focus on myself and my technique in the first two-and-a-half (kilometres) and then try to push hard in the second round," said Oestberg of her strategy. "I thought I did a good job, then on the last uphill I really tried just to focus to get to the top and send Astrid [Jacobsen] out on her leg."
"I felt the first half of my leg was OK then at the end I don't know what happened," added Jacobsen. "I was so tired, I lost so many seconds that I felt like I messed it all up but then luckily I have other girls in my team that were so strong today. It feels unreal, so many mixed emotions. We were so disappointed at finishing outside the podium last time in Sochi in 2014, so it feels like it all came together [here]."