Up 36-35 at the half, the Liberty (13-6) outscored for Storm (5-16) 24-9 in the third quarter.
Epiphanny Prince and Essence Carson each scored 11 points for the Liberty. Candice Wiggins added 10.
Seattle's Sue Bird, the first pick of the 2002 draft, was 3 of 7 from beyond the arc to score 14 points, becoming the first player in WNBA history to score 5,000 points and amass 2,000 assists.
The Liberty inducted former star Becky Hammon into the franchise' Ring of Honor at halftime. Hammon joined the San Antonio Spurs last year as the first full-time paid female assistant coach in the NBA and coached the Spurs' to a summer league title last month.