Having started his career as an assistant director, Balwinder Singh Janjua made his foray into the entertainment industry with the 2002 movie 23rd March 1931: Shaheed. He then went on to assist in movies such as Ab Tumhare Hawale Watan Saathiyo, and Apne. In 2010, he made his debut as a producer and writer with the Gurdas Mann, Jonita, Gaurav Kakkar-starrer Punjabi drama Chak Jawana.

In 2017, he wrote the screenplay and story of the Arjun Kapoor, Ileana D`cruz, and Athiya Shetty-starrer romantic comedy Mubarakan, which he was also associated with as the creative producer. The same year, Balwinder wrote the screenplay of the Kapil Sharma-starrer historical comedy Firangi, which also features Ishita Dutta and Monica Gill in pivotal roles. He then wrote the screenplay for Saand Ki Aankh (2019), Puaada (2021), Tera Kya Hoga Lovely (2024).

He also wrote the web series Cat (2022) starring Randeep Hooda in the lead.