She went on to obtain a Diploma in Legal Practice from the Law Development Centre, in Kampala, Uganda's capital city.
[2] In 2004, after admission to the Bar in Uganda, Kainobwisho joined Shonubi Musoke & Company Advocates, as a Legal Assistant, serving there for one year.
She then transferred to the Uganda Ministry of Justice and Constitutional Affairs, as a State Attorney, working there for six years until October 2011.
[2][3] In November 2011, she joined URSB as the Manager, Intellectual Property, serving in that capacity until June 2013.
[2][3][4] In December 2020, following the election of Bemanya Twebaze as Director General of the African Regional Intellectual Property Organization (ARIPO), the Board of Directors of URSB conducted interviews for his replacement and Mercy Kainobwisho was selected as the best candidate.