However, the SNP did increase their share of the vote by almost five per cent from Labour.
A Labour loss would have been the fifth such election defeat since Brown replaced Tony Blair in June 2007.
Only months ago Labour members doubted Brown's leadership as the Conservative Party surged ahead of them in the polls by as much as 20 points.
Yet, the world has come under increasing economic strain since then and Brown's stringent and resolute handling of the financial crisis has been viewed as the catalyst in reducing that lead to nine points.
Brown provided an unprecedented and lauded bailout scheme in October to counter the crisis.
With his wife Sarah, he had campaigned in Glenrothes where the death of the incumbent allowed the vote.
The win is seen as concrete evidence at the polls of what UK media are terming a "Brown bounce" - his and his party's recovering popularity.