Hartmann in 2009
|Full name||Lennart Hartmann|
|Date of birth||3 April 1991|
|Place of birth||Berlin, Germany|
|Height||1.70 m (5 ft 7 in)|
|Playing position||Defensive midfielder|
|2007–2011||Hertha BSC II||23||(1)|
|2012–2013||SV Babelsberg 03||29||(0)|
|2013–2014||Berliner AK 07||20||(0)|
|2014–2016||Tennis Borussia Berlin||44||(10)|
|* Senior club appearances and goals counted for the domestic league only and correct as of 25 February 2016.
Hartmann started his professional career with Hertha BSC, making his first appearance on 31 July 2008 in the 2008–09 UEFA Cup first qualifying round second leg against Nistru Otaci. He made his Bundesliga debut on 17 August 2008 in the opening fixture against Eintracht Frankfurt when he came on in the 67th minute to replace Gojko Kačar. The appearance made him the youngest player ever to for Hertha BSC in the Bundesliga and the sixth youngest Bundesliga player of all time, at the age of 17 years and 103 days. In January 2011, Hartmann had a trial spell with Canadian club Vancouver Whitecaps. In June 2011, Hartmann signed for the 2. Bundesliga club Alemannia Aachen. Failing to make a single appearance in six months, Hartmann left Aachen in January 2012 to join 3. Liga club SV Babelsberg 03. He left Babelsberg in July 2013 after the club were relegated to play for Berliner AK 07 in the Regionalliga Nordost, and in the summer of 2014, joined Tennis Borussia Berlin in the sixth-tier Berlin-Liga.
- "Lennart Hartmann: In der Filmstadt die Hauptrolle spielen". DFB (in German). 17 February 2012. Retrieved 11 August 2014.
- Weber, Marc (1 February 2011). "German youth international on trial for Caps". The Province. Archived from the original on 4 February 2011. Retrieved 6 February 2011.
- "Doble incorporación para el Alemannia Aachen". planetafichajes.com (in Spanish). 6 June 2011. Archived from the original on 25 March 2012. Retrieved 12 August 2011.
- "Kannste an einer Hand abzählen". Tennis Borussia Berlin (in German). 30 June 2014. Retrieved 11 August 2014.