He organized the first Nigerian Jazz festival in 1964 at King's College hall in Lagos.
In 1967, his Yaba barber shop "Sunmi's Place", was a trend-setting centre for the fashionable Lagos elite.
In 1972, he went to the U.S.A where he worked as an electronic drafter and technical illustrator. His strong visual sense made him embark on a photography course in 1976 at Foothill College in Los Altos, California. Sunmi held his first solo exhibition at Stanford University, Stanford, California, in 1978. In December 1978, he was invited by the National Council for Arts and Culture to mount an exhibition at the National Arts Theatre, Lagos. He continued to work to support his new interest until his return to Nigeria in 1982. Since then, Sunmi has consolidated his position, both as a professional photographer of international standing and leader of the field in his own country. In 1983, he became the first photo editor of the Guardian Newspaper.
He is a multi-award winner including the 3rd Commonwealth Photography Exhibition award in Hong Kong (1983).

The Sunmi Smart-Cole Gallery of Photography (probably the first in Africa) was opened in Yaba, Lagos, in 1990.

Smart-Cole's second book, "A Pictorial View: The Foreign Policy Landmarks of the Babangida Administration" (in colour/black and white), was commissioned by the President. It was published in July, 1993. His first book, "The Photography of Sunmi Smart-Cole", with foreword by Nobel Laureate Wole Soyinka (in black and white), was published by Bookcraft Ltd., in collaboration with Daily Times of Nigeria, Lagos, in 1991. Sunmi has held over 30 exhibitions in five continents.