Mario Vrančić became Norwich's third signing of the 2017 summer transfer window when he joined for German side SV Darmstadt 98 on 8th June 2017. The Bosnian international midfielder signed a three year deal for an undisclosed fee.
Mario played youth football for VfR Kesselstadt (1995-2004) before joining 1. FSV Mainz 05. After progressing from their reserve team, he made 9 first team appearances. He was loaned to Rot Weiss Ahlen in June 2009. his return to Mainz, he was relegated to the reserves, and six months later, he left the club to join Borussia Dortmund II
On 1 July 2012 he joined SC Paderborn 07 for whom he played for in the 2. Bundesliga and Bundesliga until the end of the 2014–15 season. He made 93 league appearances.
On 24 June 2015, he signed for newly promoted side SV Darmstadt 98.He played 45 games in two seasons, scoring six goals. he had played 251 professional games by the time of his transfer to Norwich.
Vrančić has represented Germany at under-17, under-19 and under-20 level.He won 2008 UEFA European Under-19 Football Championship with Germany. n 2015, Vrančić received a green light from FIFA to play for Bosnia and Herzegovina. He made his debut for the Bosnian national team on 6th September 2016 against Andorra
He made his Norwich debut in the 1-1 draw away to Fulham on the opening day of the 2017/18 season (5th August 2017)