Guillaume Matignon started playing in 1994. Guillaume claims to have received the 34thDCI number issued in France and to have played in France's very first sanctioned event. In 2002, Matignon would meet fellow French player Guillaume Wafo-Tapa at the European Championship. Later that year Matignon moved to Wafo-Tapa's hometown of Nantes to study for three years. From there the two built a strong friendship, often preparing for events together. Matignon credits this friendship as a major source of his later personal success and considers Wafo-Tapa to be his favorite player. Matignon's name first came to the attention of the community as one of the men credited with designing Pierre Canali's deck, which he used to win. In particular, Matignon was credited with the addition of to the deck, a card Canali said 'made all the difference'. At this point Matignon had not met Canali, with Wafo-Tapa being the one to pass the decklist on to Canali. Matignon's personal breakout performance came at the 2006 where he made the Top 8, losing to Selim Creiche in the quarterfinals. Matignon claims that this result made him more serious about Magic and he started to attend every Pro Tour |Pro Tour. Matignon would continue to have great success at the France National Championships going on to win the 2007 event, take 3rd place in the 2009 event, and take 2nd in the 2010 event. The French National teams that Guillaume has featured on in the Team World Championship have placed 43rd, 8th and 6th.
Matignon's greatest success came in 2010, in which he reached the finals of, and won the defeating long-time friend Guillaume Wafo-Tapa in the finals. These results combined with his 2nd place French Nationals finish and other strong finishes throughout the year resulted in Matignon coming in joint first place alongside Brad Nelson |Brad Nelson in the. This led to an unprecedented Pro Tour #Pro Player of the Year|Pro Player of the Year tie-breaker contest. The 2010 Player of the Year race was decided in a special Player of the Year Match held at Pro Tour Paris 2011. Brad Nelson won the match 4-2 and became the official 2010 Pro Player of the Year, leaving Matignon to take second place.
Suspension
On 28 April 2011, the website reported that Guillaume Matignon and fellow professional player Guillaume Wafo-Tapa, had admitted responsibility for the leak of all the cards that would be contained in the upcoming New Phyrexia set. Matignon was apologetic about the leak, revealing that it was caused when he shared the 'God Book' of all the cards in the set, which he had received in order to write an article on the set for French magazine , with Wafo-Tapa. As a result, Guillaume Matignon was suspended from the DCI for three years, but later reduced to one year. Guillaume Wafo-Tapa, Martial Moreau, and David Gauthier were also suspended until October 2012.
Guillaume Matignon took part in the first ever World of Warcraft TCG World Championships in 2007. The event took place from 30 November to 2 December in San Diego, California and featured over 400 participants. Matignon would go on to win the event becoming the inaugural World Champion and earning himself $100,000, the largest single prize in TCG history. As a result of this achievement, Guillaume Matignon is the current holder of the World Record for the 'Greatest Cash Prize for a Trading Card Game'. Before winning the World Championships of WOW TCG, Guillaume also won the National Championship in 2007.
