After beginning his youth career with TJ Košutka Plzeň and SK Plzeň 1894, Fillo joined the youth system at Viktoria Plzeň in 1996.[3] He began his senior career with 2. Liga club and helped it to promotion to the First League during the 2004–05 season.[4] In his first full season in the top flight, he made 29 appearances and scored five goals, as Plzeň narrowly avoided relegation.[5] He played 15 matches and scored five goals during the 2007–08 season, before making his last appearance for the club in December 2007.[4]
Viking
In 2008, Fillo signed a five-year contract with NorwegianTippeligaen club Viking,[6] for a club record fee which amounted to more than 15.7 million kr.[7] He made his debut for Viking on match day one of the 2008 season, assisting the winning goal and being voted man of the match in a 1–0 victory over Strømsgodset IF.[8] He scored his first goal for Viking in a 1–0 victory over Tromsø IL on match day four.[8] He appeared consistently during the 2008 season, making 28 appearances and scoring 8 goals.[8] He made 25 appearances and scored three goals during the 2009 season and played in Viking's UEFA Cup qualifiers,[8] which ended with a second round defeat to Honka.[9] During the 2010 season, Fillo made only 15 appearances, but scored five goals, including a hat-trick against Odds on 4 July 2010.[8]
Return to Viktoria Plzeň
Fillo re-signed for Viktoria Plzeň on a 4+1⁄2-year contract during the 2010–11 season and made 12 appearances, scoring one goal.[9] He won the first silverware of his career, having helped Plzeň to the First League title and he also won the 2011 Czech Supercup with the club.[9] Fillo made 9 appearances and scored one goal during the first half of the 2011–12 season and spent the second half of the season on loan at fellow First League club Mladá Boleslav.[9][10] He made 17 appearances and helped the club a fourth-place finish (one place behind his parent club Viktoria Plzeň) and Europa League qualification.[9][11]
Fillo made 27 appearances for Viktoria Plzeň during the club's First League-winning 2012–13 season.[9] He played part of the first half of the season on loan at Mladá Boleslav, making 10 appearances before returning to Plzeň prior to the winter break.[9]
In July 2013, Fillo agreed a season-long loan with EnglishLeague One club Brentford, linking up with Uwe Rösler, his former manager at Viking.[12] He scored one goal in 9 appearances,[13] before being dropped from the team in October 2013.[14] New manager Mark Warburton indicated in late December 2013 that he would hold talks with Fillo over his future.[14] Fillo was made available for loan on 19 February 2014,[15] but did not win any further calls into the first team squad before the end of the season.[9]
Fillo joined First League club 1. FK Příbram on loan for the duration of the 2014–15 season.[16] He made 27 appearances and scored two goals before his Viktoria Plzeň contract expired at the end of the season.[9][17] Fillo made 56 appearances and scored three goals in his second spell with Plzeň.[9]
Teplice
In July 2015, Fillo signed a three-year contract with First League club FK Teplice on a free transfer.[17] Over the course of 2+1⁄2 seasons, he made 73 appearances and scored 22 goals and departed Na Stínadlech in December 2017.[9][18]
Baník Ostrava
On 29 December 2017, Fillo joined Czech First League club FC Baník Ostrava on a permanent contract for an undisclosed fee.[18] He made 115 appearances and scored five goals during 3+1⁄2 seasons with the club.[9]
Trinity Zlín
On 4 June 2021, Fillo joined Czech First League club FC Trinity Zlín (then named FC Fastav Zlín) on a two-year contract for an undisclosed fee.[19][20] He made 51 appearances and four scored goals during the 2021–22 and 2022–23 seasons,[9][21] in both of which the club narrowly avoided relegation.[22][23] Fillo was released when his contract expired.[24]
Jiskra Domažlice
During the 2023 off-season, Fillo transferred to Bohemian League A club Jiskra Domažlice.[25] He made 25 appearances and scored seven goals during a 2023–24 season in which the club narrowly missed the division's promotion playoff place.[21][26][27] He departed the club in June 2024.[26]