Smith will take up her new role at the beginning of March, with Laura Butcher, who last month joined from Keep Britain Tidy, taking over the PR manager post.
The charity funds research and provides patient services to sufferers of myeloma, but is keen to end what it describes as a 'postcode lottery' for the distribution of cancer treatment Velcade.
'Public affairs is a key part of my role, and I am devising a lobbying campaign to change the way Velcade is distributed, targeting MPs and National Institute for Clinical Excellence,' said Butcher.
She described the Velcade situation as 'similar to that faced by breast cancer sufferers lobbying for Herceptin'.
The charity is also keen to raise donor contributions, and is planning to increase activity around its tenth annual awareness week in June.