|Sengupta was a finalist at the 1999 Gladrags Hunting Competition in which John Abraham was the winner. He modeled for designer Rohit Bal and worked for choreographers Marc Robinson and Achala Sachdev. He also appeared in commercials for the Tata Indigo Marina car, VIP Frenchie and Aquafina.
Later, he made the transition to music videos, including Pal Pal tere yaad sataye by Falguni Pathak and Jagjit Singh; one for Hindi album of South Indian singer Yesudas; and a remix of the old movie song "Koi diya jale kahin", sung by Asha Bhosle of the film Bees Saal Baad.
In 2004, he played in the movie Shukriya: Till Death Do Us Apart who also played Aftab Shivdasani, Shriya Saran and Anupam Kher. He had to play in the film Dus but the project was abandoned.
In 2008, he played the negative role of Mohan Kanta, a British army man who betrays his revolting independence military regiment in the 1920 horror film, written and directed by Vikram Bhatt. He also played the role of Tushaar in the television series Zee TV Banoo Main Teri Dulhan.
He appeared with his wife at Nach Baliye 3 as a late participant.He has played in Bollywood films Mumbai Salsa and Kahaani. He also made some Bengali movies. In 2008, he starred in Janala, also starring Swastika Mukherjee and directed by Buddhadev Dasgupta.
At the beginning of 2009, he played alongside Indrani Haldar in Angshumaner Chhobi, directed by Atanu Ghosh, the first filmmaker. The film was the only Bengali entry in the competitive section of the Indian Panorama in Goa. In late 2009, he played the role of a bisexual lover in Kaushik Ganguly's Arekti Premer Golpo. His love for this film is director Rituparno Ghosh, and it was Rituparno's first film as an actor.
In 2010, he directed his first commercial film Bengali, Jodi Ekdin, directed by Riingo. Indraneil received the Anandalok Award for the new face of the year in 2009 for Anshumaner Chobi.
Indraneil played the role of a young aspiring director in the Bengali Autograph film with Prasenjit Chatterjee and Nandana Sen. The film is a tribute to Satyajit Ray and Uttam Kumar as he is on the lines of the film Nayak.