Percy Schmeiser is a Canadian farmer specializing in canola. In 1998, he devised a way to obtain and use Roundup Ready seeds (i.e. seeds genetically engineered to withstand sprayings with the herbicide glyphosate) without paying the legally required licensing fees. However, he was found out and sued for patent infingement by Monsanto. Despite two appeals, he lost in the Supreme Court of Canada.
Since then, he has become a celebrity in anti-GMO circles. He is falsely portrayed as an innocent, powerless farmer who lost the fight against a giant evil agrichemical corporation which sued him because his field was contaminated with GM seeds against his will. None of the elements of the anti-GMO story actually check out.
 The actual dealings of Mr. Schmeiser
The real story of Mr. Schmeiser can be found in the court proceedings. Following his normal farming practice, Schmeiser applied the Roundup herbicide around power poles and ditches in his field to kill weeds and volunteer plants. He noticed that some canola plants survived the spraying. He proceeded to spray the edge of one of his fields with Roundup. He then collected the seed from the surviving plants to a separate truck and used it to plant the next year's crop. This was detected by a private investigation agency hired by Monsanto to conduct random audits of farmers in the area. Samples taken from Schmeiser's field indicated that almost all of the canola was Roundup Ready. The court found that this constituted a patent violation and decided in favor of Monsanto, including $200,000 in fees. However, the court declined to award punitive damages, as it could not be proven that Percy had been using Roundup on this field and thus was not unjustly enriched via the patent infringement (which brings up the question of just why the hell Percy would go to all that trouble to get Roundup Ready canola in the first place). Further counter-lawsuits by Schmeiser were either dismissed without a ruling or settled out of court.
Schmeiser went on to become a poster child for the anti-GMO movement. He was the subject of the 2009 pseudo-documentary film "David versus Monsanto", which presents his story in an extremely misleading way. For instance, it states that his field was contaminated with GM seeds against his will. This is impossible given that the GM seed content in the field was almost 100%, and contradicts his court testimony. It also claims that Schmeiser does not use Roundup, something he personally admitted doing in the court proceedings.
He has actually received two awards due to this mythology: the Mahatma Gandhi Award in 2000 "for working for the good of society" and the Right Livelihood Award with Louise Schmeiser in 2007 "for their courage in defending biodiversity and farmers' rights, and challenging the environmental and moral perversity of current interpretations of patent laws".
In an amusing coda in 2014, Schmeiser noted in an interview that GMO canola is now being grown on his farm, by a tenant of his land. Legally, presumably.
He's a member of the Liberal Party of Saskatchewan and was mayor of his hometown Bruno from 1966 to 1983, while being provincial Member of the Legislative Assembly (MLA) from 1967 to 1971. He was appointed to Saskatchewan's Real Estate Commission from 1993 to 1999.
He has been town councillor and deputy mayor of Bruno since 2003.
 See also