Slomka was manager of Tennis Borussia Berlin from 1 July 2000 to 17 November 2000.[4] Before that, he coached the U19's of the club in one season.[5] His first match was a 2–0 win against Rot-Weiss Essen on 28 July 2000.[6] His final match was a 1–0 loss to Werder Bremen II on 11 November 2000.[6]
Return to Hannover 96
In 2001, Slomka returned to Hannover as assistant manager under Ralf Rangnick.[7] He left the club at the end of the 2003–04 season.
Schalke 04
Slomka became the manager of Schalke 04 on 4 January 2006, after serving two years as assistant manager for the club.[8] His first match was a 2–0 win against 1. FC Kaiserslautern on 29 January 2009.[9] He was in charge of Schalke 04 in the year FC Schalke 04 finished second in the Bundesliga after VfB Stuttgart. He also led Schalke 04 to semi-finals of UEFA cup in year 2005–06.[9] However, they were knocked out in the first round the following season.[10] He was given a lifeline when his side knocked outPrimeira LigaChampionsPorto4–1 on penalties after a 1–1 draw on aggregate in the UEFA Champions League, but Schalke 04 were knocked out in the next round by Barcelona2–0 on aggregate, and the final spell for him was a humiliating 5–1 defeat at the hands of title rival Werder Bremen.[11] On 13 April 2008, the club management of Schalke 04 released Slomka from his obligations after several weak performances of the team.[12] Slomka finished with a record of 55 wins, 27 draws, and 26 losses in 108 matches.[13]
On 16 February 2014, it was reported that Slomka had become head coach of Hamburger SV pending the approval of the supervisory board.[23] It was approved and announced the following day.[24] He was given a contract until 2016.[24] He is the 13th head coach of Hamburg since 2004.[25] Slomka's first match in charge was a 3–0 win over Borussia Dortmund.[26] Slomka was able to pick up two more victories (1. FC Nürnberg and Bayer Leverkusen).[27] He didn't pick up a single point over the final five matches of the league season. This includes losses to Hannover 96, VfL Wolfsburg, FC Augsburg, Bayern Munich, and 1. FSV Mainz 05.[27] Despite not picking up any points over this period, 1. FC Nürnberg and Eintracht Braunschweig were unable to catch Hamburg and they finished the season in 16th place,[27] which led to a relegation–promotion play–off against Greuther Fürth. In the relegation–promotion play–off, the first leg ended in a 0–0 draw[28] and the second leg ended in a 1–1 draw.[29] The result meant that Hamburg avoided relegation.[29] Slomka was sacked on 15 September 2014 after only one point and no goals in the 2014–15 Bundesliga season.[30] His final match was a 2–0 loss against Hannover.[31] Slomka launched a lawsuit against Hamburg for €1.4 million compensation.[32] He finished with a record of three wins, five draws, and 10 losses.[33]
Karlsruher SC
On 22 December 2016, he was appointed as the new head coach for Karlsruher SC.[34] He was sacked on 4 April 2017.[35] He finished with a record of two wins, two draws, and six losses.[36]
Second return to Hannover 96
On 28 May 2019, it was confirmed that Slomka had returned to Hannover 96 for the third time as manager for the upcoming 2019–20 season.[37] The club hired him in its bid to secure an immediate return to the Bundesliga, as the club just had been relegated in the previous season. He was sacked on 3 November 2019.[38]