Rehema started her acting career in Mira Nair's Maisha Film Lab's 2008 production, Downcast where she played a housewife.
"[7] The Hollywood Reporter critic Neil Young wrote, "Nanfuka and Buyi are engaging performers and cope well with underwritten characters.
"[8] In 2013, she starred in Joel Karekezi's Imbabazi, The Pardon, a film about the Rwanda genocide, in which she was nominated for the Best Actress award at the Festival du Cinéma Africain de Khouribga, Morocco 2015.
Rehema starred as Suzanna in Yat Madit in 2016 alongside Gladys Oyenbot and Michael Wawuyo Jr. For this role, she won the award for Best Actress TV at the Uganda Film Festival in 2017.
Her other notable theatre credits include The Laramie Project, Tropical Fish (book), Jean Paul Sartre's No Exit, Just me you and the silence and the river and the mountain.