He is the son, and grandson of singers Nitin Mukesh and Mukesh, respectively.

After brief roles as a child artist in Vijay (1988) and Jaisi Karni Waisi Bharnii (1989), Mukesh decided to venture into acting after graduating from HR College with a bachelor's degree in commerce. He made his film debut in 2007 with the successful thriller Johnny Gaddaar, which earned him a Filmfare Award for Best Male Debut nomination. His first commercial success came when he garnered praise for his performance in the terrorism drama New York (2009), for which he was nominated for the Filmfare Award for Best Supporting Actor.

Following a series of Hindi films, he made his debut in Tamil cinema with Kaththi (2014), which became one of the highest-grossing films in Tamil cinema. His highest-grossing releases came with the romantic drama Prem Ratan Dhan Payo (2015), the comedy horror Golmaal Again (2017) and the action thriller Saaho (2019); the former two rank among the highest-grossing Indian films of all time.

His father is Bollywood playback singer Nitin Mukesh, son of veteran singer Mukesh. His paternal grandmother was a Gujarati Shrimali Brahmin while his paternal grandfather was a Mathur Kayastha from Delhi. He was named by Lata Mangeshkar after the American astronaut Neil Armstrong. As a child, he appeared in Vijay (1988) and Jaisi Karni Waisi Bharnii (1989) as the younger versions of Rishi Kapoor and Govinda respectively.

Neil was educated at Brown Lawns H kindergarten and HR College in Mumbai, where he graduated with a bachelor's degree in commerce at his father's insistence. He then decided to pursue a career in acting, despite being born into a family of singers. In an interview with The Times of India, the actor said "singing is my hobby, but acting is my passion. A passion that even my grand-dad harboured. So, while my father continued his legacy and became a singer, I pursued his other passion. I am living his dream". Neil trained at a four-month workshop at the Kishore Namit Kapoor Acting Institute, and received training from actor Anupam Kher.

In April 2018, Neil Nitin had announced via Instagram that they are currently expecting their first child due later on in the year. Neil Nitin was then blessed with a baby girl Nurvi Neil Mukesh on 20 September 2018.

Neil eats Gujarati food such as vatanu shaak, rotli, daal and kadhi for lunch and dinner and frequently attends dandia-raas.