Australia's best player in their T20 World Cup victory in the Caribbean last month, Healy also hit 70 in the first game of the WBBL but has only reached double figures twice in the six innings since.
She brought up her half-century in just 33 balls on Thursday, and her innings included nine boundaries and two massive sixes swept over the legside boundary off-spinner Molly Strano.
Strano (3-26) had been the only one of the Renegades bowlers to trouble the Sixers, claiming all three of their wickets in the form of Ellyse Perry (8), Ashleigh Gardner (19) and Erin Burns (4).
The win moved the Sixers back into second spot on the WBBL ladder behind leaders Sydney Thunder, while the Renegades are stranded in seventh with just two wins.
Left-arm quick Lauren Cheatle had earlier been the Sixers' best with the ball, claiming figures of 2-6 from her two overs.
Her spell included the key wicket of Amy Satterthwaite for 21, who along with Maitlan Brown (33 off 30) provided the only real resistance for the Renegades.