Born in modern-day Croatia and raised in Australia, he began his career at Perth Glory and was briefly with Juventus before moving to Switzerland's FC Basel in 2001, where he played 202 league matches.
Ergić was born in the coastal town of Šibenik in SR Croatia, SFR Yugoslavia but was raised in the near-by village of Gaćelezi.
Ergić signed his first professional football contract with Perth Glory in 1999 and helped the club finish the regular 1999–2000 NSL season as division winners.
The 2000 NSL Grand Final was held on 11 June and Glory took a three-goal lead by half time, but their opponents Wollongong Wolves pulled the game back and it ended in a 3–3 draw.
[6] Basel were able to play their home games of the championship group in their new stadium, the St. Jakob-Park which opened on 15 March 2001 and it was sold out with 33,433 spectators on three occasions.
Basel started well into the second part of the season and during this period FCB played their best football, pulling away at the top of the table and subsequently achieved the championship title prematurely.
Just four days later they played in the cup final against Grasshopper Club, winning 2–1 after extra time, thus they won the domestic double.
[10][11] In the summer of 2004, because of his depression, Ergić was sent to the University Psychiatric Clinics "UPK" Basel, where he spent four months with inpatient treatment.
[14] Subsequently, Basel dropped into the 2005–06 UEFA Cup, where against NK Široki Brijeg in the first round, they sealed a 6–0 aggregate win to qualify for the Group stage.
But then a last-minute goal from Zürich's Iulian Filipescu meant the final score was 1–2 in favour of the away team and it gave FCZ their first national championship since 1980–81.
[16] The last minute loss of the Championship and the subsequent riots, the so-called Basel Hooligan Incident, meant that the club would suffer the consequences.
In the second qualifying round they were drawn against FC Vaduz from Liechtenstein, narrowly progressing on the away goals rule after a 2–2 aggregate draw.
Winning both matches in the qualification round and both matches in the play-off round, they team advanced to the group stage, which they ended undefeated in second position, after playing 1–0 at home against Stade Rennes, 0–0 away against Dinamo Zagreb, 1–0 at home against Brann and 1–1 away against Hamburger SV, to continue the knockout stage.
[22] In the Swiss Cup via FC Léchelles, SC Binningen, Grasshopper Club, Stade Nyonnais and in the semi-final Thun, Basel advanced to the final, and winning this 4–1 against AC Bellinzona they won the competition.
[24] But in advance of their 2008–09 season Ergić resigned from being team captain and handed this job over to his teammate, Franco Costanzo.
Basel joined the 2008–09 UEFA Champions League in the second qualifying round and with an aggregate score of 5–3 they eliminated IFK Göteborg.
Here Basel were matched with Barcelona, Sporting CP and Shakhtar Donetsk, but ended the group in last position winning just one point after a 1–1 draw in Camp Nou.
[25] At the end of the 2008–09 Super League season Basel were third in the table, seven points behind new champions Zürich and one adrift of runners-up Young Boys.
Then on 16 June 2009, Ergić was released by FC Basel after newly hired manager Thorsten Fink decided not to offer him a new contract.
He made his international debut in Serbia & Montenegro's 1–1 draw with Uruguay at the Red Star Stadium in Belgrade on 27 May 2006.
[30] In June 2004, Ergić was treated for depression in the psychiatric university clinic in Basel, and his further career as a football player was in question at the time.
[31] He appeared on the Swiss late night show Aeschbacher, stating that football players earn too much money and expressing sympathies for the ideas of Karl Marx.
He also appeared on RTS (Serbian public broadcaster) programme Ključ where he openly discussed his battle with depression as well as treatment he had undergone.