She also plays for New South Wales in domestic cricket, as well as the Sydney Sixers in the WBBL and captains the UP Warriorz in Women's Premier League in India.

She moved up the state age group ranks and made her debut for the senior New South Wales team in the 2007–08 season.

During the same season, she recorded her highest score of 89 not out at faster than a run a ball, and made the most dismissals of any wicket-keeper in the Women's National Cricket League.

Following the injury to Australian captain and wicket-keeper Jodie Fields, Healy was given her international debut in the 2010 Rose Bowl series against New Zealand.

In the final, she scored a quickfire 75 off 39 balls against India to help Australia win their fifth title and won player of the match.

[2] Despite the family heritage, and watching her uncle represent Australia, she said that she did not become interested in cricket until she moved from Queensland to Sydney as a child and was coaxed into taking up the sport by a friend.

Her selection at the age of 16 in late 2006 as wicket-keeper for Barker College First XI, the first time a girl had been picked to play among boys in the elite private schools' cricket competition in New South Wales, drew press commentary from various sources.

[9] The sportsmaster of Barker College condemned the anonymous writer as "gutless" and maintained that Healy's selection was based on merit.

[9] Ian Healy and Alex Blackwell, a cricketer for the Australian women's team and former Barker student, also defended the selection and criticised the email author.

[14] At the start of the 2007–08 season, she made her senior debut for the New South Wales Breakers in the Australian domestic one-day league.

[14][17] New South Wales reached the final and were awarded the title because they placed first in the qualifying matches after rain washed out the deciding game.

[14] She scored 120 runs at 40.00, took six catches and made three stumpings, and was recalled to the senior team after one week in the second-string outfit.

[20] In the final against the same team the following week, Healy made 11 from 22 balls before being run out, but New South Wales nevertheless won by six wickets with more than 15 overs to spare to claim the title.

[14] After the Women's World Cup held in early 2009, Coleman transferred to play for the Australian Capital Territory, so Healy became New South Wales' wicket-keeper on a full-time basis for the start of the 2009–10 season.

Coming in upon the fall of Leah Poulton with the score at 1/9 after three overs, she hit 13 fours in 82 balls, putting on partnerships of 72 with Blackwell and 82 with Sthalekar.

New South Wales reached their target of 187 with more than 13 overs to spare and Healy was named the Player of the Match, having earlier taken a catch and made a stumping.

In reply, Healy made a duck as New South Wales lost four wickets in the first 13 balls and were all out for 75 to lose by 22 runs.

[29] Healy was selected in the Australian squad for the Rose Bowl series against New Zealand in February 2010 due to an injury to the incumbent wicketkeeper and captain Jodie Fields.

The selection committee released a statement saying "Alyssa has been identified for higher honours for a number of years and now gets the chance to display her wicket-keeping skills and attacking batting on the international stage".

New Zealand batted first and Australian fast bowler Ellyse Perry extracted an outside edge from captain Aimee Watkins from the first ball of the match.

[33][34] Watkins went on to score 44 from 36 balls as New Zealand made 7/117 and Healy's only dismissal was to catch Nicola Browne from Sthalekar's off spin.

It would have gone for a match-winning four runs but for New Zealand wicket-keeper Rachel Priest diving across and catching the ball one-handed in her right glove, handing the tourists a two-run victory.

[14][33][34] Healy had little impact with the bat in the three T20s in Australia and two more at the start of the New Zealand leg of the series, scoring 17 runs at 5.66 and a strike rate of 77.27.

She caught Deandra Dottin from the bowling of Perry for a golden duck as Australia won by nine runs to finish the group stage unbeaten at the top of their quartet.

Healy stumped leading Indian batter Mithali Raj from the bowling of Sthalekar and was not required to bat as Australia reached their target of 120 with seven wickets and seven balls to spare.

[41] Australia elected to bat first in the final against New Zealand, but the top-order struggled and Healy came to the crease to join Elliott at 5/51 in the 13th over after the fall of two wickets in quick succession.

[43] During the middle of the run-chase, Priest was incorrectly given out stumped by Healy after the television umpire Asad Rauf had pressed the wrong button, and he had to retract his decision.

She was named ahead of Australian Women's Vice-Captain Rachael Haynes and Sydney Sixers Captain Ellyse Perry.

[76] Alyssa Healy holds the world record for the most runs in a Women's T20 International with 148* (61) at North Sydney Oval on 2 October 2019 against Sri Lanka.

[5] On 8 March 2020, Healy recorded the fastest 50 (off 30 balls) in the history of ICC event finals across formats before it was broken by Heinrich Klaasen in 2024.