He will oversee the jury for the PR category at the annual festival taking place between 16 and 22 June, which celebrates its 60th anniversary this year.
Gallagher said: 'This festival offers a rise-and-shine moment on a global stage for the PR community, and I’m honoured to take part in selecting the very best of our creative efforts from around the world.
'It’s not only an opportunity to represent Ketchum at the centre of what’s generally recognised as our industry’s most important creative gathering – it’s also a chance to work together with global practitioners from other agencies to examine and judge some of the boldest and brightest creative work that’s taken place around the world in the past year.'
As president he will be hoping to quell controversy in the PR category, which continued last year when it was dominated by advertising agencies, with the top prize bagged by creative agency JWT for the third year in a row.
The PR Lion was inaugurated in 2009, making Gallagher only the fifth person to serve in this role.