Park joins the service, which seeks to recruit new blood and organ donors, from Newcastle City Council, where he was assistant director of policy and comms for seven years.
Before this, Park was head of comms for Cumbria Council for nearly five years.
Park has also worked in government departments, having served as a senior press officer for the Home Office and head of communications strategy for the then Ministry of Agriculture Fisheries and Food, as well as a stint in the Metropolitan Police comms team.
Commenting on his appointment, Léonie Austin, director of marketing and comms at NHS Blood and Transplant, said: "Steve joins us at a crucial time as we address the challenge of changing public attitudes to organ donation so people expect to donate if they can and strive to engage new blood donors to meet patient need, particularly from the black community as those suffering from Sickle Cell Disease benefit from closely matched blood."