Alongside the takeover, Zoe Howorth has joined Houston PR's board as a non-executive chair and Alice Kain has joined as a non-executive board member.
Howorth brings a wealth of international experience with consumer brands and was previously the UK marketing director at Coca-Cola.
Kain is a former head of communications and investor relations at FTSE 250 private equity investor SVG Capital. She brings more than 20 years' financial PR and investor relations experience to the board.
Houston PR, founded and previously owned by Hamish Thompson, works with a broad range of clients, from household brands to innovative start-ups and listed companies, including John Lewis, Virgin Money, easyHotel and One Water.
Houston has doubled in size in recent years and expanded its capability to include corporate and financial PR, delivering integrated campaigns for clients while keeping its creative heritage at its core.
Houston said the fresh investment will allow the business to grow as it continues to scale that offering.
Its team specialises in all disciplines of public relations and marketing communications and aims to produce high-impact, creative campaigns that engage multi-stakeholder audiences.
"I have worked with the Houston PR team for many years and I’m thrilled to be joining the business at this exciting time for the consultancy and the industry," Howorth said.
"I look forward to working with the team to expand Houston PR’s capabilities and to further develop their unique approach to consumer, corporate and financial public relations."
Thompson added: "Houston has always been a business that favours giant leaps over small steps. I’m delighted that we’ve assembled this world-class team and proud that we have the backing of our new investors."