Brown moves up from the role of agriculture development manager, a position he has held since joining Asda five years ago.
A spokesman for Asda said that Brown, in a new role for the retailer, would focus on ethical and sustainable sourcing on the farming side of the business, reporting to Asda's executive food trading director Darren Blackhurst.
Brown has worked at Asda for five years and previously reported to fresh trading director Andy Adcock. He was also responsible for milk buying but this role has been taken over by Jonathan Betts, who is also responsible for cheese. Prior to Asda, Brown was an agricultural technologist at Marks and Spencer. He said: "I'm delighted to step into this new role. Over the past few years we've led the way in many areas, from local sourcing to dedicated dairy farmers. But there's plenty more to do, such as switching all our fresh fish to MSC in the next three to five years. I'm looking forward to meeting that challenge head-on."
During his time at Asda, Brown has been involved in a number of high-profile agricultural initiatives.
Perhaps his most significant achievement was overseeing the switch to a single sourcing arrangement for own label liquid milk.
Under the arrangement, Arla Foods UK supplies all Asda's milk needs from a dedicated pool of farmers, who receive a premium for their raw product.
Last week the retailer also announced a two-year cheese deal with Dairy Crest in a bid to bring stability to suppliers' businesses.
Meanwhile, this week, in an effort to reduce food miles, Asda said that it had started a trial in Cornwall for a group of farmers to start delivering produce direct to stores instead of via a distribution depot.