Fun fact:

He was born born John Sidney Blyth. His father was Maurice Barrymore, an Indian-born British actor who had been born Herbert Blyth, and had adopted Barrymore as a stage name after seeing it on a poster in the Haymarket Theatre in London.[9] --WP

And they stuck with that stage name forevermore. By contrast, I kinda like how 3/4 of Ramón Estévez' (Martin Sheen's) kids stuck with the original name, with only Charlie going with the stage name.

Barrymore's mother, Georgie Drew Barrymore, was born into a prominent theatrical family.

Another interesting little tidbit is the way they revisited the Drew name in later generations, even using the Southern USA practice (I think it is) of applying it as a first name, as with the famous actress.