He joins Lansons this week following eight years as a director at Citigate Dewe Rogerson.
Baldock has worked for several listed companies including both M&A and IPO consultation and most recently offering media relations advice for the IPO of retailer GAME Digital.
Tony Langham, co-founder and CEO, said: "One area where we’re seeing particular growth is our corporate work and we already represent more than 40 listed companies.
"As soon as we met Tom we recognised that he has the right experience and attitude to head our City practice, deliver results and drive growth."
Baldock said: "I was attracted by its solid track record and the strong ambition that it has for the future. It’s an exciting time to be joining a growing agency with such clear values and vision, and one in which I will be able to play such an integral part."