Faksa began his ice hockey career in his birth city ofOpava, although at age 11, his single mother was struggling to fund his hockey career. Faksa and his family received an offer from HC Oceláři Třinec for Faksa to play in Třinec's system, whereupon the Faksas accepted the offer; Faksa moved alone to Třinec, where he lived by himself in a hotel paid for by his team until the age of 17. Faksa was drafted 22nd in the CHL Import draft by the Kitchener Rangers of the Ontario Hockey League. In his first season with the Rangers, in 2011–12, Faksa primarily played on the team's second line, scoring 29 goals and 37 assists for 66 points in 62 games in his first season of North American hockey. Faksa's draft stock rose throughout the season and he solidified himself as a top prospect, ranking fourth on the NHL Central Scouting Bureau's midterm ranking of North American skaters. He was then selected to participate in the 2012 CHL Top Prospects Game, where he won the “Showdown Breakaway Challenge” in the Top Prospects Skills Competition. Faksa finished the season as the rookie leading scorer in the OHL, also finishing second in voting for the Emms Family Award, awarded annually to the OHL's top first-year player; the Award ultimately went to 15-year-old defenceman Aaron Ekblad. On 22 June 2012, Faksa was drafted 13th overall by the Dallas Stars in the 2012 NHL Entry Draft. He was the first Czech taken in the first round of an NHL Entry Draft since Jakub Voráček's selection in 2007. In addition, Faksa was drafted seventh overall by the Kontinental Hockey League 's Neftekhimik Nizhnekamsk in the 2012 KHL Junior Draft. On 10 January 2014, Faksa was traded by Kitchener to the Sudbury Wolves in exchange for fellow Czech Dominik Kubalík and two second-round draft picks.
Professional
On 6 July 2012, Faksa signed an entry-level contract with Dallas. Upon completing his junior career with Sudbury, on 3 April 2014, Faksa was reassigned by the Stars to their AHL affiliate, the Texas Stars. Faksa scored his first NHL goal on 6 November 2015 in a victory over the Carolina Hurricanes. On 28 November 2017, Faksa tallied a natural hat trick in the second period, scoring the only goals in the Stars' shutout of the Vegas Golden Knights. It was the first hat trick of his NHL career as well as the first scored in T-Mobile Arena and the first time the Golden Knights were shut out at home. The following game, on 30 November in Chicago, Faksa was hooked by Patrick Kane on a shorthanded breakaway and awarded his first career penalty shot, which he scored on to give the Stars a 2-1 lead in the first period. Faksa notched an assist in the second period on a pass to Remi Elie, and the Stars went on to beat the Blackhawks 4-3 behind an overtime goal by Mattias Janmark.
