He was regarded as a two-way player who can stop the opposition and start attacks with his passing from central midfield.

Born in Hanover, Ernst started his career with hometown club Hannover 96.

[1] The midfielder moved to Werder Bremen in 2000, where he was a major force in the league helping the club win the double of Bundesliga and DFB-Pokal in the 2003–04 season.

On 16 September 2010, Ernst headed in a last-minute goal against Bulgarian side CSKA Sofia to help his team to a winning start in the group stages of the UEFA Europa League.

In July 2020, Beşiktaş J.K. and Ernst announced that their cooperation to establish youth academies across continental Europe,[6] focusing in Germany, Austria, and the Netherlands.