a/the grand old man

the grand old man of (something)

The most senior and respected man in a particular organization, society, etc. His decades of hosting charity balls and galas have made him the grand old man of London.
See also: grand, man, of, old

a/the ˌgrand old ˈman (of something)

an old man who is very experienced and respected in a particular profession, etc: At eighty, he is the grand old man of the British film industry.
See also: grand, man, old