Leffen

On 16 February 2016 Leffen became sponsored by Red Bull as an official Red Bull Athlete. As of 2018, he was no longer with Red Bull.

On 29 April 2016 Leffen announced that his Form I-129 petition to obtain a visa had been denied by United States Citizenship and Immigration Services. On 4 May 2016 it was initially announced that Team SoloMid was able to secure a P1 Visa for Leffen so he can be able to attend US-based tournaments throughout July which includes EVO 2016. TSM is working on extending this visa for the long term. However, 14 July Leffen announced that he had run into additional delays in the visa approval process and would miss EVO. Finally, on 3 October, Leffen's visa was approved, allowing him to compete in US-based tournaments again, in time for The Big House 6, a year after his deportation. In August 2018, Leffen won Evo 2018, defeating Armada 3-0 in grand finals to claim the trophy.

In VGBootCamp's Apex 2015 Salty Suite, Hjelte defeated Kashan "Chillin" Khan in a first-to-five set without dropping a single game. Because of this, Hjelte has the "rights" to use Fox's default color. Joseph "Mango" Marquez subsequently challenged Hjelte to a US$ 1,000 money match if they were to face-off in the Apex Singles bracket. Hjelte would in turn beat Mango when they played in Winners' Semifinals. After defeating Jason "Mew2King" Zimmerman at Apex 2015 in singles bracket, Hjelte has taken at least one set off each of the "five gods" of Melee. Hjelte ultimately finished third in Apex 2015 Melee singles.

On 9 March, Hjelte was signed by Team SoloMid as its first player on their Super Smash Bros. division, as well as their first fighting game player. In the aftermath of his Apex 2015, Leffen is now viewed as being on par with the Melee gods. The melee community often debates Leffen's exact title with regards to the Melee gods. Some say that due to his ability to beat all of the gods he is officially considered one of the gods, while others state that the term Melee God refers to players who were dominant for a period of time from 2008-2014 and that Leffen instead fits the title of Godslayer better. It is due to this division in the melee community that most analysts and commentators refer to the Melee Gods and Leffen as the Big Six, with Leffen being the person who officially ended the era of the gods. At CEO 2015 in Orlando, Florida, Leffen won his first American major, defeating Armada. He placed 5th at EVO 2015 later that year, despite being a favorite to win. He was upset by Panda Global's Justin "Plup" McGrath who played Samus. Melee it on Me ranked Leffen as the 2nd best player in the world in their summer 2015 mid-season rankings. Leffen was barred from entering the United States just before The Big House 5 tournament because he was travelling on an Electronic System for Travel Authorization (ESTA) and employed by US-based Team SoloMid.

Hjelte has competed in fighting games including Dragon Ball FighterZ, Ultra Street Fighter IV, Ultimate Marvel vs. Capcom 3, and The King of Fighters XIII. In an interview with EventHubs prior to Apex 2015, he suggested he might play Guilty Gear Xrd on his Twitch stream after Apex 2015 concluded.

He placed 9th in the Swedish national tournament B.E.A.S.T 2 within his first year of playing Melee. Throughout 2014 Leffen began placing highly in tournaments and defeating the top five Melee players regularly. Prior to EVO 2014, Joe Cribari of Nintendo Enthusiast listed Leffen among the three "underdogs" with the greatest chance to win the tournament. He finished 9-12th at EVO 2014.

Leffen was previously a controversial figure in the Super Smash Bros. community, where he has been called a "villain" due to acts of bad sportsmanship, including insults targeting other players and online forum posts inciting drama. He was banned from attending tournaments in Sweden and from SmashBoards for much of 2013 because of these reasons. The accusations against Leffen were contained in a Zip file called "evidence.zip".

Hjelte started playing Super Smash Bros. in 2009, when he was introduced to Super Smash Bros. Brawl. He initially started as a Yoshi and Falco player before switching to Fox. Leffen feels that he made the gradual switch from Falco to Fox because he views Falco as requiring more discipline and Fox being more suited to his play style.

William Peter Hjelte (born 16 October 1994), better known as Leffen, is a Swedish professional gamer who competes in Super Smash Bros. Melee, Dragon Ball FighterZ and Super Smash Bros. Ultimate. In Melee, he plays as the character Fox, and is considered one of the best players in the world, finishing in the top six in formal rankings in 2014, 2015, 2016, 2017, and 2018. Hjelte is the first of two players to have beaten each of the "Five Gods" — Juan "Hungrybox" Debiedma, Joseph "Mango" Marquez, Adam "Armada" Lindgren, Jason "Mew2King" Zimmerman, and Kevin "PPMD" Nanney — in a tournament set and was also the first person outside the "Five Gods" to win a major tournament since 2010 when he did so in 2015. He placed first in the Super Smash Bros. Melee tournament at Evo 2018. He is sponsored by Team SoloMid.