This is 73-year-old Bachchan's fourth National award. He previously won the honour in 1990 for "Agneepath", for "Black" in 2005 and for "Paa" 2009.
Ranaut, 28, won the award for her role in romantic comedy drama "Tanu Weds Manu Returns" for her endearing dual turn as Tanu, a troublesome wife and Haryanvi sportsperson Datto. It is her third trophy at the National Awards, having earlier won best supporting actress for "Fashion" and best actress "Queen" last year.
Sharat Katariya's debut "Dum Laga Ke Haisha", a '90s set drama in Haridwar about the romance between a mismatched couple, was named the best Hindi film.
Sweeping historical romance "Bajirao Mastani" helped its director Sanjay Leela Bhansali win the best director honour.
Salman Khan-starrer cross-border drama "Bajrangi Bhaijaan" was named best popular film providing wholesome entertainment.