Hoxhallari started his youth career at KF Tirana. On 1 July 2011 he was loaned out at Austrian side Grazer AK for a half season.
Hoxhallari made his professional debut for Tirana on 23 November 2011 in the cup tie against Apolonia Fier, playing full-90 minutes in a 3–0 home win. That was his first and only appearance of the 2011–12 season. Hoxhallari found more opportunities in the 2012–13 season, making his league debut on 13 April 2013 in a 2–1 deficit at Kukësi. In the 2013–14 season, Hoxhallari continued to get limited opportunities, as he made only nine league appearances, eight of them as starter.
On 29 August 2014, Hoxhallari was transferred to Teuta Durrës on a long season loan from Tirana along with Ardit Peposhi. Initially Hoxhallari struggeled to play as he did not leave the bench for the first four league matches. On 1 October, he made his debut by scoring the team's first goal of the 2–0 away win against Besëlidhja Lezhë in the first leg of 2014–15 Albanian Cup first round. Four days later Hoxhallari made his league debut in a 1–0 away defeat to Kukësi, playing full-90 minutes. Following the debut, Hoxhallari established himself in the starting lineup, and went to play another 25 league matches until the end of the season as Teuta Durrës barely avoided the relegation to Albanian First Division.
On 1 June 2015, he returned in training with Tirana after the end of loan. He made his first appearance of the season on 29 August in team's second league match of the season against Laçi, where he entered in the pitch on the last 15 minutes as Tirana found the equalizer in the very last moments. With Shkëlqim Muça in charge, Hoxhallari was used mostly as a substitute, and during his tenure at the club, Hoxhallari played only one league match as a starter, the 2–0 home win against his previous side Teuta Durrës on 26 September. With the arrival of the new coach Ilir Daja, Hoxhallari become an undisputed starter and went to play as a started in every league game until the end of the season, as Tirana remained out of European competitions for the fourth straight season. He was praised for his performances on the back and on 31 May was named one of the talents of the year.
On 14 July 2016, Hoxhallari agreed a contract extension with the club, signing until June 2018. He scored his first league goal for Tirana on 6 November in the matchday 10 against his former side Teuta Durrës, contributing in a 3–1 home win. Later on 10 March 2017, he scored a free kick as Tirana denied Skënderbeu Korçë the win. During the course of 2016–17 season, he made 34 league appearances, scoring twice, and Tirana was relegated for the first time in history, finishing 9th. He also scored once in 7 cup appearances in team's successful campaign, which saw them win the trophy for the 16th time, setting a new record.
Hoxhallari kicked-off 2017–18 season by playing in the 2017–18 UEFA Europa League first qualifying round against Maccabi Tel Aviv. He played in both legs, also making his European debut in the process, as Tirana was eliminated 5–0 on aggregate. Hoxhallari started the domestic season by playing in the 2017 Albanian Supercup against Kukësi on 6 September 2017, netting a 90th minute winner via a shot outside the box as Tirana clinched their 11th Albanian Supercup trophy. Tirana also set a record by becoming the Albanian First Division side to win the Supercup.
He has been a former Albania youth international, playing with under-15, U-17, U-19, U-20 and U-21 levels.
Hoxhallari received his first international level call-up at age of 14 by coach Sulejman Demollari of the Albania under-15 squad, which were just founded in 2009 for participating in the 2010 Summer Youth Olympics (Football).
He made his under-15 debut on 17 October by featuring full-90 minutes in the match against Liechtenstein which ended in a 2–0 win. Then the team advanced to the final where they faced Montenegro two days later, losing 1–2 as Hoxhallari played another full-90 minute match, missing their participation in the 2010 Summer Youth Olympics finals.
Hoxhallari was called up at Albania national under-20 football team by coach Skënder Gega to participate in the 2013 Mediterranean Games football tournament which began on 19 June 2013 in Mersin, Turkey. Hoxhallari played in all 5 Albania U20s matches as full 90-minutes. Albania U20 was ranked in the last place out of 8 teams.
Hoxhallari was called up for the first time in under-21 squad by the coach Skënder Gega for the qualifiers of the 2017 UEFA European Under-21 Championship, where Albania was placed in the Group 4. He made his competitive debut with the under-21 side on 28 March 2015 in team's first group match against Liechtenstein, playing in the second half in an eventual 2–0 away win. Hoxhallari was called up by a new appointed coach, Redi Jupi, for the next qualifying matches against Israel and Portugal on 3 and 8 September 2015. He played full-90 minutes in the 1–1 home draw against Israel, and was benched in the 1–6 home defeat against Portugal. On 28 March 2016, during the match against Hungary, Hoxhallari made a high profile error which resulted in Hungary's only goal of the match, but Albania bounced back and scored twice inside of 10 minutes for a 2–1 home win.As of 16 September 2017
Albanian Cup: 2011–12, 2016–17
Albanian Supercup: 2012, 2017
Albanian Superliga Talent of the Season: 3rd in 2015–16 season