The 33-year-old upset Bolivian 25th seed Hugo Dellien 6-3 6-3 to lead the Australian charge on day one of action at Melbourne Park.
Olivia Gadecki was also a first round winner, the 23-year-old Queenslander setting up a clash with former world No.3 Sloane Stephens.
Other Australians to bank opening wins included Tina Smith, Lizette Cabrera and Dane Sweeney, who overcame Italian 26th seed Andrea Pellegrino 6-2 4-6 6-3.
Tomic, who last played in the Open in 2021 when he reached the second round, looked fit and focused in his Monday afternoon match.
While he appeared relaxed, Tomic said he felt on edge but was buoyed by the vocal support from the stands.
"I was a little bit nervous as well at the start; I haven't played many big matches in the last year," said Tomic, who mostly plays on the ATP Challenger Tour.
"The atmosphere was incredible, it was really good to be out there.
"The Aussie fans have always been there, it's always been great. It felt special.
"So I'm happy I'm back winning - I think it's my first match I've won in a while here in quallies or main. So for me it's really good, so let's see if I can win another couple, that would be nice.
"It's something that has been my goal - to qualify at a slam again, to have a bit of a run at a grand slam."
Ranked some 50 places lower than world No.138 Dellien, Tomic broke to lead 3-1 with six aces helping him comfortably take the first set.
He went ahead 4-2 in the second before wrapping up the match in 72 minutes.
Tomic will next face British youngster Arthur Fery, after the world No.185 overpowered Australian wildcard Edward Winter 6-2 6-4.
Gadecki eased past her Dutch opponent Arantxa Rus 6-2 6-4 and will next face Stephens, who is the only major winner playing in qualifying this week for a spot in the main draw.
The 32-year-old, who won the 2017 US Open and reached the semi-finals of the Australian Open in 2013, was sidelined for seven months last year with a foot injury.
Her WTA ranking dropped outside the top 1000, forcing the American into qualifying for the first time since Wimbledon in 2012.
She opened her account on Monday with a 6-1 7-5 victory over Czechia's Barbora Palicova.
While keeping alive Stephens' hopes of playing in a 14th Australian Open, the win ended a horror 13-match losing streak.
"The last match I won was Wimbledon 2024," Stephens said post-match. "I obviously had a bumpy road on the back of that, then got injured at the beginning of last year and didn't play.
"I'm not going to be like, 'Oh my god, I played so bad'. It was never that. Time passes, things happen and it's unfortunate."
World No.171 Gadecki and Stephens have met three times before with the Australian leading the head-to-head 2-1.
"I played her here two years ago, and then another few times," Stephens said.
"I know her game and I'm familiar with her, and she's a great player and I'm just going to go out and hopefully continue to play good tennis."
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