Glasgow-born, London-based Kalu was announced as the winner of the award – and its £25,000 prize money – at a ceremony in Bradford, the UK’s current city of culture, on Tuesday.
She accepted the honour while wearing a rosette bearing her photo and the words: “Idol, legend, winner, whatever.”
Kalu has been gradually gaining recognition in the art world in recent years after working as a resident artist with Action Space, which supports artists with learning disabilities, since 1999.
Ms Hollinshead, her studio manager and artistic facilitator, said: “We are so happy that Nnena’s talent and beautiful work is now out in the world for you all to see this complex artist who creates gorgeous, complex forms – all while listening to disco music, often as loud as possible.
“Nnena’s career reflects the long, often very frustrating journey we’ve been on together… to challenge people’s preconceptions about differently abled artists, but especially learning disabled artists, an important creative community so undervalued.
“When Nnena first began working with Action Space in 1999, the art world was not interested.
“Her work wasn’t respected, not seen, and certainly wasn’t regarded as cool.
“Nnena has faced an incredible amount of discrimination, which continues to this day, so hopefully this award smashes that prejudice away.
“Nnena Kalu, you’ve made history!”