Ramsdale worked at the LSC for 16 months, and was made redundant as part of major cutbacks that began eight months ago.
His CIPR role includes lobbying to ensure universities and colleges delivering PR courses are well funded.
He has replaced Gerald Chan, who joined the Royal College of Obstetricians and Gynaecologists in February as head of comms and external affairs.
Chan has recruited a team of three. He wants to attract medical students to the specialism, which has recruitment problems.