Answered by: Maulana Abrarul H. Hasib
Did Prophet Muhammad celebrate his birthday?
In the name of Allah, the Most Gracious, the Most Merciful
Rasul Sallallahu Alaihi Wasallam celebrating his own birthday is not substantiated or established in the Qur’an, Hadith, from any Sahabah (RA), Tabi’een, nor any Taba Tabi’een. No example has been found in their lifetime of celebrating His (SAW) birthday.
This Bid’ah (innovation) came into existence by the command of Muzaffar Uddin in the year 604 AH, who was extravagant and wasn’t a practising Muslim king. 
Hence, celebrating His (SAW) birthday is merely baseless, innovation and not proven from Rasul Sallallahu Alaihi Wasallam.
Only Allah knows best
Written by Maulana Abrarul H. Hasib
Checked and approved by Mufti Mohammed Tosir Miah
Darul Ifta Birmingham
 Fatawa Darul Uloom Zakariyya, Vol. 1, Pg. 266, ZamZam Publishers.
 Aap Ke Masa’il Awar Un Ka Hal, Vol. 1, Pg. 445, Maktabah Ludhyanwi.
 Fatawa Uthmani, Vol. 1, Pg. 105, Maktabah Ma’ariful Quran.