Prior to his ascension to the Osu Stool (or throne), Nii Okwei Kinka Dowuona VI had served the Osu state in different capacities. He had been a member of the Kinkawe Asafo (warriors of Osu's Kinka Quarter), Secretary to the Dzaase (kingmakers) and also Secretary of the Osu Traditional Council. As a male member of the royal Dowuona House, one of the two Osu royal houses (the other being the Owuo House), Nii Okwei Kinka Dowuona VI was in line to be enstooled king during the protracted chieftaincy dispute that had wracked the Osu state for decades. His service to the traditional authority had brought him to the attention of the stool fathers and therefore stood him in good stead to leverage his lineage. In the interim, however, another claimant, Nii Nortey Owuo III (also known as David Nortey Ashong), had held himself out to be King of Osu for several years, tracing his lineage through the Owuo House, though he was unable to secure the support of key stakeholders regarding his eligibility. On 4 May 2007, the accredited Dzaase in collaboration with the Wulomo (chief priest) and the leadership of the two royal houses, successfully installed Nii Okwei Kinka Dowuona VI as substantive Maŋtsɛ or King at the Osu Klottey Shrine located in the confines of the Osu Castle. This state of affairs resulted in high drama that year when both Nii Nortey Owuo III and Nii Okwei Kinka Dowuona VI led rival processions to celebrate the Ga Homowo festival in August, though Nii Nortey Owuo had custody of the Osu Palace and received government functionaries and other traditional rulers in his capacity as Osu Maŋtsɛ. The recognition given by government officials to Nii Nortey Owuo III during the festival and other functions provoked angry reactions from the Osu Traditional Council, which insisted that it recognised Nii Okwei Kinka Dowuona VI and not Nii Nortey Owuo III as Osu Maŋtsɛ Both sides litigated the matter in the courts, and a decision by the High Court in Accra in March 2010 settled the dispute in favour of Nii Okwei Kinka Dowuona VI. Following this development, on May 2, 2010, the National House of Chiefs formally gazetted or entered the name of Nii Okwei Kinka Dowuona VI into the National Register of Chiefs as recognised Osu Maŋtsɛ . The National House of Chiefs also expunged from its records the name of Nii Nortey Owuo III as Osu Maŋtsɛ, revoking and withdrawing the document previously issued to him recognising him as Osu Maŋtsɛ, noting that as far back as 1992, the Government of Ghana had passed Executive Instrument (EI) 31 (Osu Stool Property (Seizure and Restoration) Instrument), which ordered the City Manager of Accra to take possession of the Osu Stool Property until a legitimate chief was enstooled. The House of Chiefs regarded EI 31 as effectively destooling Nii Nortey Owuo III. The Nii Nortey Owuo III faction continued to contest the enstoolment of Nii Okwei Kinka Dowuona VI, and when the latter was officially installed as Paramount Chief of Osu in May 2010, police had to fire rubber bullets to prevent the disruption of the event. However, Nii Okwei Kinka Dowuona VI subsequently exercised full substantive powers as Osu Maŋtsɛ , and was recognised by the Government of Ghana, politicians and traditional rulers in Ghana and abroad, as well as the public. His position as Paramount Chief of Osu made him the traditional landlord of the Government of Ghana and he was recognised as an authority on custom and tradition.
