Hayes joins from distiller Whyte & Mackay, where he held the same title and was responsible for the relaunches of the eponymous whisky brand, Vladivar vodka and Jura malt whisky.
He fills the post vacated by Roz Cuschieri, who was promoted to commercial director in October 2005. Hayes will be part of the senior commercial team reporting to Cuschieri, alongside sales director John Smethurst and Sarah Miskell, who has been promoted from category marketing controller to category director.
Warburtons has a 22% share of the £1.7bn plant bread market, ahead of Hovis' 21% and Kingsmill's 14%, according to Mintel.
The brand launched its first national TV advertising campaign in January this year, focusing on its reputation as a family-run business and using the strapline 'Bakers born and bred'.