Houghton joins Nunwood after a 16-year career at Millward Brown. Prior to this, she worked at GlaxoSmithKline.
Clare Brue, chief executive of Nunwood, said: "We are committed to recruiting the very best people in our industry and Sarah brings a wealth of agency and client-side experience combined with strong commercial acumen and leadership, which will strengthen an already talented team of client account directors at our London office."
The newly created managing director role comes four months after Nunwood opened its London office.
The London operation has been opened to spearhead a new business drive aimed at London-based FTSE 100 companies, increase staff recruitment prospects and to improve the level of service offered to existing clients based in the capital.
The office works across existing Nunwood clients in addition to new clients such as InBev. Other clients include Nokia, BSkyB, Heinz, Becks, Britvic and Tesco.com.
Nunwood, which has its headquarters in Leeds, last month opened its first international office in New York.
The new office came on the back of strong growth in 2006, including 40 new clients. Nunwood said sales in the first quarter of 2007 are up 78% against the same period last year.