8 November 2013, Stieber scored three goals in two matches against Erzgebirge Aue and scoring twice against Paderborn. Stieber went on to score three goals later in the 2013–14 season against Sandhausen (which he also scored against them in another encounter in the last game of the season) and Fortuna Düsseldorf. In his final season for Fürth, in the 2. Bundesliga, he scored 9 goals and made 11 assists in total of thirty–six appearances. Hamburger SV 2014–15 and 2015–16 seasons On 26 May 2014, Stieber signed for Bundesliga club Hamburg. In an interview with Nemzeti Sport, he admitted that he had signed the most lucrative contract of his career. Stieber was spotted by the Hamburg managers during the relegation play-offs of the 2013–14 Bundesliga season against Fürth. The first tie ended with a goalless draw, while the second tie finished with 1–1 which resulted that Hamburg could remain in the top flight of the Bundeliga. Stieber gave the assist on the return match. Stieber made his Hamburger SV debut on 30 August 2014, where he played 45 minutes, in a 3–0 loss against Paderborn. In January 2015, Stieber played for the first time as a center in Hamburg against Eintracht Frankfurt in a friendly match. On 4 February, he scored his first goal in the 2014–15 Bundesliga season in a 3–0 victory over Paderborn in the 91st minute at the Benteler Arena, Paderborn, Germany. On 7 February 2015, he set the record of the highest distance in the 2014–15 Bundesliga by running 13.9 km against Hannover 96 at the Imtech-Arena, Hamburg. Later in the 2014–15 Bundesliga, Stieber scored his first goal against Borussia Mönchengladbach at the Imtech Arena, in Hamburg on 22 February 2015. For the first time, he was able to score a goal in a consecutive match against Eintracht Frankfurt at the Commerzbank-Arena in Frankfurt on 28 February 2015 in the 2014–15 Bundesliga. However, the match ended with a 2–1 defeat for his team. Stieber ended the 2014–15 season, making thirty–eight appearances and scoring three times in all competitions. In the 2015–16 season, however, saw Stieber's first team opportunities increasingly limited despite being fired up ahead of a new season. Stieber made his first appearance of the 2015–16 season, where he came on as a substitute for Nicolai Müller in the 87th minute, in a 1–0 win over 1899 Hoffenheim on 23 October 2015. In January transfer window,