The CatererSearch 100 list - compiled to mark the launch of Caterer's new website - recognises key players whose actions are having the greatest impact on the sector in 2005.
Criteria included: direct power; wider influence within the industry; financial success; innovation and longevity.
Oliver took the number-one position largely as a result of his recent TV series, Jamie's School Dinners, which has had a huge impact on the school meals market.
The programme's associated campaign forced the Government to stump up an extra £280m for school meals after 270,000 people signed Oliver's petition calling for better nutritional standards.
Ironically, runner-up Mackay heads the contract catering giant whose education catering subsidiary Scolarest bore the brunt of Oliver's criticisms in the programme.
Last week Mackay announced that he would be stepping down from his position early next year.
Third place in the CatererSearch 100 was taken by Hilton Group boss David Michels, while fourth went to another celebrity chef, Gordon Ramsay. Alan Parker, who heads restaurants-to-hotels group Whitbread, was named as fifth most influential person in the industry.
The judging panel for the list was made up of senior journalists from Caterer & Hotelkeeper, sister magazine Chain Leader UK and CatererSearch.
To view the full CatererSearch 100, click here.