After his return to West Africa in 1841, he first became a Methodist minister and, after his resignation from that position, a diplomat in the Ashanti Empire and the British Gold Coast.

In April 27 of that year, he and his cousin Nkwantabisa were handed over to the British as hostages, part of the Maclean treaty ending the first Anglo-Ashanti war.

They were given a farewell tour of Great Britain as well as an annual pension of £100, for which they were expected to promote British interests and visit the Gold Coast governor twice a year.

They arrived back in West Africa in July 1841, where they lived with the governor for four months before travelling to Kumasi in November and December.

He married Sarah Scott, a Fante woman of mixed African and British heritage who he had met in Britain.

[1] In the same year, the Methodists granted him a three-week leave to Kumasi during a diplomatic crisis involving the Ashanti Empire.

There, Asantehene Kwaku Dua I commissioned him to write a letter to the British Gold Coast governor dispelling rumours about a possible Ashanti invasion.

He again played a large role in bringing an end to the second Anglo-Ashanti war, volunteering to negotiate with the leader of the Ashanti army, Owusu Koko.

Most of that time was spent as captive of the new Asantehene Kofi Karikari, who wanted to use his literary abilities and prevent information about a planned Ashanti attack on the Gold Coast from leaking out.

[1] During the war, in January 1873, a mob stormed Owusu-Ansa's house in Cape Coast and killed five Ashanti members of his household.

[1] He returned to Cape Coast in 1874, where he faced British repression for trying to assist Ashanti rebuilding efforts.

In 1883, Owusu-Ansa played a role in an Ashanti succession crisis, but the British ordered him to return to Cape Coast.