Gustav Harkort attended the trade school in Hagen, and after completion, began a commercial apprenticeship in his father's company.
In 1813 he took part in the German Campaign of 1813 as a lieutenant in the Märkisches Landwehr Regiment.
He was the chairman of the board of directors of the Leipzig-Dresden Railway Company from its foundation in 1835 until his death.
In 1864, on the 25th anniversary of the completion of the Leipzig-Dresden railway, Harkort was named an honorary citizen of the city of Leipzig.
On 9 July 1878 a monument designed by the architect Carl Gustav Aeckerlein (1832–1886) in collaboration with the sculptor Eduard Lürssen (1840–1891) was inaugurated in Leipzig.