8 September] 1843, in the Alexander Palace in Tsarskoye Selo south of central Saint Petersburg, during the reign of his grandfather, Emperor Nicholas I. Nicknamed "Nixa", he was the eldest son of the Tsesarevich Alexander Nikolaevich, eldest son of Emperor Nicholas I, and the Tsesarevna Maria Alexandrovna of Russia.

"[1] His history teacher said, “If I succeeded in forming a student equal to Nikolai Alexandrovich once in ten years, I’d think I’d have fulfilled my duties.

Pretty, direct, intelligent, lively yet shy.”[5] As he continued on his European tour, he wrote love letters to Dagmar every day.

Nicholas's symptoms at that time included back pain and a stiff neck, as well as sensitivity to noise and light.

It was eventually determined that he was suffering from cerebro-spinal meningitis, and it was speculated that this illness of his was caused by a previous accident in a wrestling match, in which Nicholas participated and was thrown down.

On his deathbed, Nicholas expressed the wish that his fiancée become the bride of his younger brother and future Tsarevich, Alexander.

In 1867, construction was begun on a chapel named in his honor (fr:Chapelle du tsarévitch Nicolas Alexandrovitch) in Nice, on the exact place where Nicholas was said to have died, and in 1868, the chapel was inaugurated, with his brother Alexander and his wife, the re-christened Maria Feodorovna, in attendance.