a/the grand old man (of something)
a man who is respected in a particular profession that he has been involved in for a long time元老;资深前辈;老前辈- James Lovelock, the grand old man of environmental science詹姆斯 · 洛夫洛克,环境科学的元老
CultureGrand Old Man was a title originally used to refer to William Gladstone, who spent many years in British politics in 19th century and was prime minister four times.
See also grand | man | old