The newly created role will see Walsh assume responsibility for Ketchum's consumer client roster. He will also be responsible for generating new business, an agency spokeswoman told PRWeek.
Ketchum London CEO Denise Kaufmann added that the agency's consumer practice was "growing", saying "we are excited to offer Mark’s deep and unique consumer brand expertise to our clients".
Walsh, who started in the role earlier this month, will report to Ketchum London deputy CEO Jo-ann Robertson.
Prior to joining Ketchum, Walsh spent several years in a variety of roles at PR firm Citizen Relations. Before leaving his role at the agency's Hong Kong office in February, he was client service director at the London office. Before this he was head of consumer technology between 2012 and 2016, his LinkedIn profile states.
He also held the role of senior account director at Hill+Knowlton Strategies between 2010 and 2012.
Omnicom-owned Ketchum is ranked as the 15th largest PR firm in the UK this year, recording revenue in the UK of £25.6m in 2016.