The original company was founded by T. L. Pelling and C. H. Stanley, who created Pelling Stanley and Company in 1857. The company soon specialized in importing canned food, which at the time was a novel product. By 1879, they were importing canned salmon from the John West company in Oregon, USA. Pelling Stanley purchased the rights to use the John West name in 1888. The first shipments of John West Salmon appeared in 1892.

By 1924, the three companies, operating separately, were all associated with Unilever:

• Angus Watson and Co.
• R B Green and Co.
• Pelling Stanley and Company

By 1964, Unilever had merged the three into one company, John West Foods. Branches were expanded to Australia and Africa in 1974.

In 1997, Heinz acquired the brand and the majority of the John West Food company operations, excluding those in Australia, New Zealand and South Africa which continued to be part of Unilever.  In March 2006, Heinz sold its European Seafoods business to French-based MW Brands, itself owned by Lehman Brothers banking group, for EUR 425 million.

In 2010, Thailand-based seafood processing company Thai Union Group bought MWBrands, resultantly becoming the world’s largest canned-tuna producer.

Info gleaned from Wikipedia