A veteran of Indian theatre with more than 45 years on stage across Gujarati, Hindi, and English, Utkarsh Mazumdar belongs to the Nagar community — a Gujarati lineage with deep roots in music and literature. He studied English Literature at St. Xavier's College, Mumbai, holds a Kovid in Sanskrit, and trained as a classical vocalist; his theatre apprenticeship was under Satyadev Dubey, Laxmikant Karpe, and Arvind Thakkar. He worked for years as a Programme Executive at Doordarshan Kendra (Rajkot, Ahmedabad, and Mumbai) before turning to the stage full-time.

In 1985 he co-founded the theatre group Arpana with Sunil Shanbag, Akash Khurana, and Shishir Sharma, directing its debut production Uljulool — a translation of Aadya Rangacharya's Kannada play. With Arpana he went on to play the tycoon Gokuldas Gandhi in Sunil Shanbag's Maro Piyu Gayo Rangoon (2007) and Rao Bahadur Gokuldas Sawaram Bhatia — substituting for the King of France — in the Gujarati All's Well That Ends Well at Shakespeare's Globe-to-Globe Festival (London, 2012). He is one of the few living performers with first-hand experience of the Bhangwadi-tradition of Gujarati musical theatre, a subject he discussed at length with Manoj Shah in the 2015 eNatya Chaupal session 'Reminiscing the Bhangwadi Days of Gujarati Theatre.'

His collaboration with Manoj Shah / Ideas Unlimited reaches back to Master Phoolmani (1999) — based on Satish Alekar's Begum Barve, written by Chandrakant Shah, with a Bhupen Khakhar backdrop — in which he played the clerk Sumanlal and contributed to the score. Other long-running stage work includes Tran Gujarati, Black With Equal, Going Solo, Devna Didhel, Meghani Sarvani, Jagi Ne Jovu To, and Nadira Babbar's Footnotes of Life — Haashiye Zindagi Ke (Ekjute Mumbai), which travelled to the Qadir Ali Baig Theatre Festival in 2019.

On screen, his best-known role remains Sardar Vallabhbhai Patel in Shyam Benegal's Samvidhaan: The Making of the Constitution of India (2014). His film credits include Raees (Dr. Sajanwala), Baazaar (Chairman Chhedha), Satya, Krazzy 4, Ventilator (Gujarati), Short Circuit, Saptapadii, and Yeh Hai Bakrapur. He also writes a Gujarati newspaper column and has taught Mass Communications.