She is the latest addition to the agency's growing public affairs practice, with her appointment coming just weeks after WA recruited Naomi Harris, former chief operating officer at Newington Communications, as a director.
Townsend has joined from investment-management firm the Octopus Group, where she spent more than four years as head of public affairs.
She previously spent a decade working in Parliament for Conservative MPs such as Justine Greening, Sir Malcolm Rifkind and Sir Peter Bottomley.
Townsend was a Conservative candidate in the 2015 election, where she was runner-up to Labour MP Clive Lewis.
In her new role at WA, Townsend will work on clients in the energy, transport, education and children's services sectors.
She started this month and reports to Dominic Church, the agency's managing director.
Revenues at WA – which was founded in 1991 as Westminster Advisers and is one of the UK’s top 150 consultancies – rose 25 per cent in 2018 to £3.8m.
Townsend said: "WA quickly stood out to me as an agency that truly operates differently to other established players in the market. Its genuine commitment to put clients first and to challenge the status quo was unmistakable and immediately attracted me to this growing consultancy."
Church commented: "It's an exciting time in public affairs as we now have a government with a strong majority, and there is more scope for domestic policy to move forward again."
He added: "Lisa will provide our clients with extensive advocacy experience and a strong understanding and insight into the Conservative government. We are absolutely delighted to have her on board."
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