The 15-year-old Plymouth College student not only became the first swimmer from her country to win an Olympic medal she did it under extraordinary circumstances.
The start, a time when swimmers are already battling their nerves, was delayed by a technical malfunction that saw the starter's gun go off before he had called "on your marks". American Breeja Larson dived into the pool on the gun but was able to race because of the malfunction.
The eight finalists sat down while the problem was fixed and an unfazed Meilutyte still got off the blocks fastest and led at the turn but then had to survive a fierce challenge from American Rebecca Soni, the reigning world champion in the event.
The more experienced Soni drew level in the final few strokes but Meilutyte kept her cool and got her hands on the wall first in one minute, 05.47 seconds.
Soni was second in 1:05.55 while Japan's Satomi Suzuki finished third in 1:06.46.
Australia's Leisel Jones, the defending Olympic champion who won a silver medal at the 2000 Sydney Games when she was 15, finished fifth overall in her fourth and final appearance at the Games.
Meilutyte is at the same school that British diving star Tom Daley attended.
Chinese swimming sensation Ye Shiwen set herself up for a golden double when she posted the fastest qualifying time in the semi-finals of the women's 200 metres individual medley.
The 16-year-old, who shattered the world record to win the 400 medley on Saturday, was untroubled booking her place in the 200 final, winning her semi-final in two minutes, 08.39 seconds.
Despite easing off on the final freestyle leg, Ye still finished well clear of her main rivals to emerge as the nearly unsinkable favourite to snatch the gold.
"I just train well and perform well and keep on going," she said.
Ye was nearly a second and a half ahead of her nearest rivals, led by Alicia Coutts, and nearly three seconds clear of Stephanie Rice, the gold medallist in Beijing four years ago.
"I just went in and swam my own race," Coutts said.
"She (Ye) might have gone 2:06 tonight. You just don't know what is going to happen. I just wanted to make the final."