The 23-year-old, who triumphed in Rio last summer alongside Laura Kenny, Elinor Barker and Jo Rowsell Shand in the team pursuit, won both the scratch race and tempo race to lead the omnium by eight points at the halfway stage.
Archibald's campaign for victory was dealt a blow in the elimination race, however, finishing fifth as Australia's Amy Cure drew equal at the top to make for a nervy finale.
Katie Archibald claims omnium gold in worlds
And tense it was as Archibald – the current European champion – held a slender two-point lead heading into the final sprint of the points race, with Cure and Dutch cyclist Kirsten Wild hot on her heels.
But the Brit dug deep and found another gear for the final lap, soaring down the last straight to secure the all-important two points that would seal top spot in the standings with an amassed total of 123.
UCI Track World Championships: Day 3: Archibald gets gold for GB
"I thought it was all over, I really thought I was done for," she said. "But then I went for it single-minded, and thought I was either getting on Cure's wheel, or Wild's wheel and then just following it.
"I stuck there until the end and then just emptied the tank.
"I was so worried I'd lose this and put myself in the red, and then lose tomorrow [Saturday], but this is mine now and I can't lose it tomorrow.
"I feel really privileged to pull it off.
"It feels very strange, I'm used to having my girls, my team-mates, around me so it's odd to celebrate by yourself but I'm looking forward to catching up with them at the hotel."
Britain's Katie Archibald waits to start the women's omnium elimination race at the Hong Kong Velodrome during the Track Cycling World Championships in Hong Kong on April 14, 2017.
Image credit: AFP
Elsewhere in the day's action, 21-year-old Ryan Owens secured his berth in the last eight on the men's sprint, beating Canada's Hugo Barrette to the line to sail into Saturday's quarter-finals.
Team sprint Olympic champion Callum Skinner couldn't follow in his tracks however, falling to a second-round exit at the hands of Germany's Max Niederleg.
"The field were three or fourth tenths ahead of my pace and it makes it difficult when you come up against the second seed," said Skinner, who also won individual silver in Rio.
"It's just a reflection of where we are. I can't be too disappointed."
In the men's individual pursuit, Matt Bostock and Andy Tennant placed 13th and 14th respectively, the former of whom was making his first appearance at a World Championships.
And in the points race, Mark Stewart missed out on the medals, finishing in seventh position with 11 points to his name over 160 laps.