Dario simic started his career in the Croatian club Dinamo Zagreb. He made his debut in 1992. In Dinamo Zagreb Simic won the Croatian First league five times. After a good performance in Croatian team in the 1998 FIFA World Cup Simic was signed to Inter Milan in January 1999.
In Inter Milan he never established himself as a regular in the first team. In a trade with AC Milan in 2002 he was swapped with ܭit Davala. He also played 13 games in the UEFA Champions League of 2003 in which AC Milan later won. Simic did not play in the final on Old Trafford.
Dario Simic has 95 caps for the Croatian national team. He played in the UEFA Euro in 1996- He was also in the squad in the FIFA World Cup Croatian team in 1998, 2002 and 2006. He is the only player who has featured in all of Croatia?s major tournaments. Simic is also the player in Croatia with most caps for the national team.