[1] He has an elder brother, Abhishek Nigam, who is also an actor, and their mother runs an NGO and a beauty parlour.

[10] Taran Adarsh of the entertainment portal Bollywood Hungama reviewed, "Siddharth Nigam is a talent to watch out for, he's superb!".

[11] Writing for India Today, Suhani Singh said, "He lights up the screen with his self-assured performance and charming presence".

[12] After his successful debut in film, he debuted on television in 2014 with the role of Young Rudra in the mythological drama series Maha Kumbh: Ek Rahasaya, Ek Kahani,[13] which aired on Life OK.[14][15] In February 2015, Nigam was seen in the historical drama series Chakravartin Ashoka Samrat where he played the lead role of Young Ashoka,[16][17] and in the same month, he appeared as a guest in a special Mahashivratri episode on Comedy Nights with Kapil.

In 2017, he portrayed the character of Bindusara, the son of Emperor Chandragupta Maurya, in Chandra Nandini opposite Avneet Kaur.