The stylish Southpaw, who is the Indian team's vice-captain in the format, was the country's highest scorer in the format in 2021 with 255 runs at an average of 31.87.
England's Nat Sciver has been named the captain of the side while Amy Jones will be donning the wicket-keeping gloves.
Mandhana was shortlisted for the top award along with Tammy Beaumont of England, Lizelle Lee of South Africa and Gaby Lewis of Ireland.
Harmanpreet Kaur has been the T20 captain since 2016 but her inconsistent run as a batter doesn't make her an automatic choice to replace Mithali in the longer formats.
While Mithali had 738 points, Smriti had 710 points in her kitty in the batting ranking, which had South Africa's Lizelle Lee at the top with 761 points.
Raj, who has 738 rating points to her kitty, is behind Lizelle Lee (761) of South Africa and Alyssa Healy (750) of Australia as there was no change in the top-10 batters from the previous rankings.
Mandhana, who faced 64 balls, punished the bowlers with 14 fours and three sixes, equalling Australian batter Ashleigh Gardner's highest individual score in WBBL history.
Mithali Raj, Smriti Mandhana remain in top 10; Taylor, Matthews advance in ICC women's ODI player rankings
Veteran pacer Jhulan Goswami was at the second place among ODI bowlers, while Deepti Sharma stayed at the fifth position in the ODI all-rounder rankings.
The 21-year-old Rodrigues, a top-order batter for the Indian women's team, slammed nine fours during her 56-ball 75 to power Melbourne to 142 for five.
Besides Mandhana, the WBBL also features Shafali Verma, Jemimah Rodrigues, Poonam Yadav, Radha Yadav, Richa Ghosh, Harmanpreet Kaur, and Deepti Sharma.
While Mandhana has 709 rating points and Verma has 726, Australia's Beth Mooney climbed a spot to top the chart with 754 points.
One of the biggest reasons for zeroing in on Mandhana as a potential leader is the fact that she is an inspiration for the younger players in this team.
India thus ended their Australia tour heartbroken, having already lost the three-match ODI series 1-2 before drawing the rain-marred lone historic day/night Test.
India vs Australia women: Harmanpreet & Co look to play aggressive T20 game to end tour on high note
Criticised for her consistent failures and after losing her place in the 50-over set-up, Jemimah Rodrigues' made a sensational comeback with an unbeaten 49 off 36 balls in the first T20I.
kipper Harmanpreet Kaur's return from an injury layoff will make for a heavyweight presence in the Indian batting line-up.