Vodafone is also planning to expand into new markets, primarily in central and eastern Europe.
On the tech side, bandwidth requirements for multimedia services have become a serious issue for the firm, which is keen to expand its Live! 3G product.
Kirk has been Ambassador to Finland since 2002, and has held a number of senior positions at the Foreign and Commonwealth Office since 1982.
He starts in April, based at Vodafone's head office in Newbury, and will report to group strategy director Alan Harper.
Kirk's duties will be similar to those of ex-group public policy director Stewart White, who left to join Bell Pottinger Public Affairs as chairman last year.