The Congo Free State's agents took over Katanga with a brutality which caused many refugees to come to Crawford's mission, which was the origin of his nickname 'Konga Vantu' which means 'gatherer of the people'.
Crawford was an individualist who did not work well for long in the company of his seniors or colleagues, but he did much to travel around the Luapula valley founding and encouraging other outposts of the Garenganze Evangelical Mission.
When the latter rebelled against and was defeated by the British, Crawford and his mission colleagues had a role in persuading the chief to accept the inevitable and to achieve a working relationship with the colonial authorities.
He wrote two influential books, of which one, Thinking Black was recommended reading for those Europeans who wanted to work in partnership with, rather than over, Africans.
One of Dan Crawford's grandchildren is Mairi Hedderwick, author and illustrator of the Katie Morag series of children's picture books.