He began his career as a director in 2011 with the film, Pyaar Ka Punchnama produced by Abhishek Pathak, Panorama Studios and Viacom18 Motion Pictures. The film is a romantic comedy which depicts the life of three young bachelors.[4] In 2013, he wrote and directed Akaash Vani. Two years later, in 2015, he co-wrote and directed the sequel of Pyaar Ka Punchnama, Pyaar Ka Punchnama 2. The sequel too received much appreciation and performed well at the box office.[5][6] He directed the film Sonu Ke Titu Ki Sweety in 2018. The film performed exceedingly well at the box office,[7] although it holds a 40% rating on Rotten Tomatoes, based on 10 reviews.[8] All four of his directorial ventures starred Kartik Aaryan and Nushrat Bharucha in lead roles.
In December 2019, it was announced that Ranjan will direct a romantic-comedy, titled Tu Jhoothi Main Makkaar starring Ranbir Kapoor and Shraddha Kapoor in the lead roles. It went on floors in January 2021 and was released on 8 March 2023, coinciding with Holi.