Please consider the following scenario:
- a) I'm really jealous of him; he's a really successful engineer.
b) Instead, I'm really proud to have such a colleague! You see! He's been a truly diligent person thoughout his whole academic period and now he's enjoying his life! I knew him since many years ago! I remember well; he really burned the midnight oil to get where his is now!
Does the bold phrase above mean to work hard late into the nights for a long time in modern English? Doesn't is sound old-fashioned to you?
I would appreciate it if you let me know a better idiom in modern language if it's an obsolete type of implying this meaning in English.