[1] Following small roles in several films, he became known for starring in the series Paatal Lok (2020–2025) and Rocket Boys (2022–2023), receiving nominations for the Filmfare OTT Awards.

[7] In 2020, Singh starred as Imran Ansari, a young, idealistic cop in the Amazon Prime Video crime thriller series Paatal Lok.

[11] In 2022 and 2023, he portrayed Vikram Sarabhai opposite Jim Sarbh's Homi J. Bhabha in the Sony LIV drama series Rocket Boys.

[12] Journalist Anuj Kumar of The Hindu opined, "As the genteel but determined Sarabhai, Ishwak Singh proves to be an effective foil to Sarbh.

[17][18][19] The critic Saibal Chatterjee labelled Singh's performance as a deaf-mute man accused of being a foreign spy as "at once expressive and mystifying".