For one thing, he is not American; for another, he has neither a university degree nor a diploma from a prestigious business school. He has not developed his reputation by running a huge global account. He is the former agency mailroom boy made good, an ambitious agency staffer who learned how to manage by doing the job.
Now he is about to face his sternest test. For too long, Y&R in general, and its US operation in particular, has been a shadow of its former self.
Beset by internal strife, it has been slow to transform itself from a classic Madison Avenue agency into a versatile operation ready to meet changing communication demands. Without radical change, Y&R may go down in history not as a network renowned for the depth of its client relationships but as one which, with its initial public offer, enriched key managers who subsequently walked away clutching their cheques.
Of course, it would be easy to brand Y&R's decision to pluck McLennan out of its Australian branch office to run the store as an act of desperation.
Even more so when the group has decided to promote from within, having spent more than a year looking for a suitable candidate. Nor have top agency managers with reputations built in the southern hemisphere always found it easy to replicate their success in more complex and sophisticated northern markets.
However, a shrinking world is changing mindsets. Who would have thought a non-Frenchman would be in charge of the Publicis network? Yet Rick Bendel, an Englishman, is its chief operating officer. And in McLennan, Y&R has an intuitive instead of a textbook manager, who has proved he can identify an enfeebled agency's potential and will not shirk from making tough calls to achieve it.
Moreover, the common features between Australia's and the US's culture may make it easier for him to be accepted in New York. Britons, regarded as more insular, do not have such a good track record in this respect.
Certainly, he will be riding in with hopes high for his success. And not just within the network. A communications world in which Y&R is not a powerful force can only be a poorer place.