In the newly created job, he will report to Alice Macandrew, group comms director at the travel operator.
D'Alfonso will be responsible for developing and implementing an effective government affairs strategy for Thomas Cook, working across Westminster, Whitehall and in Brussels, according to a Thomas Cook statement.
Macandrew joined the firm in November having previously worked at Sky. D'Alfonso's appointment continues Macandrew's reshaping of the firm's comms operation following substantial reputation damage suffered last year over the way it has handled the deaths of two children in Corfu ten years ago.
She said that D'Alfonso "brings with him a deep understanding of the industry and its issues, giving him a great basis from which to start to re-establish Thomas Cook as a leading voice for travel and tourism".
A native Canadian, D'Alfonso began his career in the office of Labour MP Barry Sheerman, and then moved to agency GovNet Communications.