The rower and five-times Olympic gold medal winner raised more than £1.75m for his charity, the Steve Redgrave Trust, when he ran the marathon in 2006.
Figures from the website JustGiving.com put him a long way ahead of his rivals with former Labour spin doctor Alastair Campbell in second place, having raised more than £300,000 for a leukaemia charity.
Other celebrities in the top 10 include former boxer Michael Watson, Peter Andre and his ex-wife Katie Price.
JustGiving MD Anne-Marie Huby said: “The London Marathon is the largest annual fundraising event on the planet and runners have raised a mind-boggling £500m for charity since the race started in 1981.
“Of this amount, £116m has been raised via JustGiving.com over the past decade. We are delighted to see the incredible efforts of the celebrities who use JustGiving.com matched by those members of the public and we look forward to continuing to support their accomplishments in the future.”
Among the celebrities set to run this year’s marathon on Sunday are impressionist Ronni Ancona and singer Will Young.