The Russian arrived at Melbourne Park as the 30th seed after failing to impress at Grand Slam level since returning from a doping ban in 2017
But the 31-year-old shrugged off her advancing years and the scorching Australian conditions to prevent Dart winning a game in their 63 minute encounter.
Sharapova, a winner at Melbourne Park in 2008, said she was feeling positive after "tough times" in her career.
"I love what I do, I love competing and challenging myself to get better," she said.
"The youngsters are coming up and they'll eventually take our place but not just yet, we want a little more time."
The former world number one was far from perfect, committing three double faults and eight unforced errors.
But she was never threatened by 22-year-old Londoner Dart, who made a hesitant start against her childhood idol.
Sharapova pounced on the Briton's weak second serve to repeatedly break her opponent, bringing up the first set bagel after 31 minutes.
The second set followed the same pattern, with Dart finally put out of her misery trying to save match point when she hit a return wide despite having an open court before her.
"Despite my opponent not having the best day, you still have to get the job done," Sharapova said.
Sharapova has served up double bagels at least five times on tour, including two in a row at the 2013 Australian Open against fellow Russian
Olga Puchkova and Misaki Doi of Japan in the first two rounds of the tournament.
She was on the wrong side of the ledger when American Lindsay Davenport beat her 6-0, 6-0 at Indian Wells in 2005.
Results from Day 1 of the Australian Open on Monday:
Aryna Sabalenka (BLR x11) bt Anna Kalinskaya (RUS) 6-1, 6-4
Maria Sharapova (RUS x30) bt Harriet Dart (GBR) 6-0, 6-0
Rebecca Peterson (SWE) bt Sorana Cirstea (ROU) 6-4, 6-1
Markata Vondrousova (CZE) bt Evgeniya Rodina (RUS) 6-3, 6-2
Petra Martic (CRO x31) bt Heather Watson (GBR) 6-1, 6-2
Sachia Vickery (USA) bt Ysaline Bonaventure (BEL) 2-6, 6-4, 6-4
Caroline Garcia (FRA x19) bt Jessika Ponchet (FRA) 6-2, 6-3
Donna Vekic (CRO x29) bt Kristina Mladenovic (FRA) 6-2, 6-4
Astra Sharma (AUS) bt Priscilla Hon (AUS) 7-5, 4-6, 6-1
Katie Boulter (GBR) bt Ekaterina Makarova (RUS) 6-0, 4-6, 7-6 (10/6)