The victory clinched a back-to-back championship run for the girls, who beat Hayward last year in the finals of the annual classic.
The players reside in Portola Valley, Woodside and other nearby towns.
Seeded No. 1 in the tournament, the Hoosiers ran off five straight victories over two days to capture the crown.
In the Final Four, Redwood prevailed over cross-bay rival Hayward, 33-29, and claimed the championship by holding off a surging Anaheim team, 39-37, when Anaheim's desperation 3-pointer at the buzzer rimmed out.
Redwood was paced by high-scorer Lauren Rally, who averaged 17 points in the tournament. But Rally was sidelined early in the third quarter of the championship game with a broken rib sustained in a fierce collision while driving to the basket.
The six remaining players, two of whom — point guard Lauren Lete and shooting guard Shelbi Aimonetti — were playing on taped-up sprained ankles, kept Anaheim at bay with a spread four-corners offense. Center Angelina Mapa averaged 10 rebounds a game and forward Ellie Shannon chipped in 6 points and 8 rebounds per game.
Reserves Jennifer Lucian and Cammie Merten locked down on the defensive end, helping Redwood limit its opponents to an average of 31 points per game, while Redwood average 45 points per game.
In both contests in the Final Four, the score was tied in the fourth quarter, but Redwood managed to outdistance their opponents each time. In the semifinal against Hayward, Lete hit a driving layup in traffic to put the Hoosiers up for good with 1:30 to go in the game. In the final, Lete hit two free throws with 35 seconds remaining to give Redwood the margin of victory.
This is the third championship in the last five years for the Redwood team, coached by Hillsborough resident Patrick Shannon.