[3] From May to November 1898, he participated in a geological expedition headed by K. J. V. Steenstrup (1842-1906) to the Disko Bay region at the west coast of Greenland.

From this expedition Moltke made paintings of geological structures, a.o., the coast line of Nugsuark Peninsula, and of the Inuit, a.o., "Greenland women in umiak".

[3] During 1902–1904, Harald Moltke joined The Literature Expedition (Den Litterære Ekspedition), headed by Ludvig Mylius-Erichsen (1872–1907), with Knud Rasmussen (1879–1933), Jørgen Brønlund (1877–1907) and Alfred Bertelsen (1877–1950).

The expedition was a dog sled journey along the unmapped north-west coast of Greenland from Upernavik to Cape York close to Thule.

He also illustrated the book Grønland, illustreret Skildring af Den Danske litterære Grønlandsekspedition 1902-1904 (1906) with Ludvig Mylius-Erichsen as author.

[3] During the later years of his life, Moltke made numerous paintings, particularly portraits and landscapes, and published his memoirs in two volumes: Livsrejsen (1936) and Den lykkelige Rejse (1941).