The side from White Hart Lane had already eclipsed former Premier League Bedford on goal-difference but lost top spot to Norfolk-based Acle in midweek.
But they hosted the leaders in Sunday’s showdown and ran out 4-1 winners to take the title by two points.
Haringey had needed the win and although they went behind to a goal from Meagan Todd, they quickly levelled with a Brooke Hills free-kick.
Klesha Darroux gave the home side a half-time lead with a shot from the corner of the box and Anele Komani got the third when winning a penalty and converting at the second attempt.
Roxanne Eshun then returned a poor clearance in stoppage-time to complete the scoring at 4-1.
On becoming Eastern Region champions, the team who lost their manager to cancer just months ago, said on their fb page:. ‘It’s has been the hardest season for every single one of us. Steve Browne, we cannot thank you enough for bringing us all together and believing in us, We did it for you.’
