How much does a low undergraduate CGPA affect chances of getting a faculty job in a top-tier university? Your undergraduate CGPA is quite low, but you were somehow accepted into a respected Masters and PhD program, and completed your postgraduate work quite successfully. Your undergraduate major was the same general field as your postgraduate research. 

You are now beginning your academic job search. How would the low CGPA affect your chances of getting a job at a top-tiered academic institution in the US or UK? 

If yes, then what else can you do in the meantime to counteract the negative effects of that low CGPA?

(btw, I am asking this for a friend, not for me as I am not in academia)
As you have already done Masters and PhD, your CGPA in undergraduate is least to be bothered. If you are in academia, your quality of research matters more than the grades that you have obtained long back in undergraduate studies.  

As your credential will grow, your resume will be filled with much more valued contents rather than just grades.