In 1767 he joined as a medical officer to the Tranquebar Mission and on his voyage to India, he passed through Cape Town where he met Governor Rijk Tulbagh with an introduction from Linnaeus, collecting plants in the Table Mountain region from 1 to 28 April 1768.
[4][5][6] In 1773, he received the Doctor's degree in absentia from the University of Copenhagen possibly for his studies on indigenous remedies published as De remediorum indigenorum ad morbes cuivis regioni endemicos expuguandos efficacia.
He became naturalist to the Nawab of Arcot in 1774 and embarked on a trip to the mountains north of Madras and to Ceylon, a description of which was later published in a Danish scientific journal.
On 17 July 1778, König was appointed Naturalist at Madras with the British East India Company where he remained until his death, undertaking several scientific journeys and working with notable scientists like William Roxburgh, Johan Christian Fabricius and Sir Joseph Banks.
[9] König made several visits around the region and perhaps the most notable of his journeys was to Siam and the Malacca Straits in 1778–80, in this period he spent several months studying the flora and fauna in Phuket.