Brady (pictured) has been managing partner at the agency, and MD, corporate, since 2011. He joined 10 years ago, initially as special advisor to chairman and founder Matthew Freud and the late Lord Philip Gould, before building up the consultancy’s corporate practice, The Brewery.
Freuds said The Brewery now generates half of the agency's revenue.
Freud said: "Arlo has been a core part of our senior leadership team, developing the Brewery into a world-class corporate communications consultancy. I have absolute confidence in his ambition and believe he will continue to drive our business forward with a real commitment to excellence and market differentiation."
Brady said: "It’s an incredible privilege for me to have the opportunity to lead freuds in this next phase of its evolution. Right now we have a combination of formidable talent, commitment to excellence and a compelling culture - I have great faith in the future."
Brady becomes the third CEO in the agency’s 32-year history.
McGuinness stepped down last November after two years in the role. It was not clear at the time how, or indeed whether, McGuinness’ role would be replaced.
McGuinness was credited with strengthening Freuds' top team and striking new partnerships with Virgin Money, McCain and London & Partners. However, under his leadership Freuds also lost the flagship Asda account, as well as PepsiCo’s corporate work and the HomeAway business.
Freuds generated revenue of £37.4m in 2016, up 29 per cent on the previous year, with the corporate offer a major reason for the growth. It moved the agency from eighth to fifth in the PRWeek UK Top 150 Consultancies table.