With Finals out of reach part way through the chase, that did not deter Healy who hit one of the fastest WBBL centuries on record to help the Sixers reign in 184 to win under the Duckworth Lewis Stern method due to a rain delay at North Sydney Oval.
The Stars had posted 4/178 from 19 with Australian captain Meg Lanning (77) top-scoring. The Sixers reaching victory with two balls to spare.
Healy, who received a standing ovation at North Sydney Oval for her knock, reached her 100 from just 48 balls. She struck 15 fours and six sixes in what was her fourth Big Bash hundred.
"Really happy with the way I struck the ball and probably the areas I was trying to target, I’m pretty pleased with that, but ultimately it didn’t get us into a Finals series, so it will probably be just a bittersweet one," Healy said.
It was the second successive 100-run partnership with captain Ellyse Perry (31). The pair following 104 on Saturday night against the Melbourne Renegades with a 150-run stand.
Perry passed 3,000 WBBL runs and joins Australian teammate Beth Mooney as the only player to achieve that in Big Bash cricket, male or female.
South African allrounder Marizanne Kapp claimed 3-34 to finish the campaign with 13 scalps.