Born on 17 December 1977 in Kosamba, a village in the Surat district of Gujarat, Hemant Kher came up through Jawahar Navodaya Vidyalaya, took a B.Sc. in Chemistry at the Maharaja Sayajirao University of Baroda, and then trained for three years at the National School of Drama, New Delhi (2000–2003). He moved to Mumbai in 2006 with his Kya Tum Ho debut, and quickly built a parallel career as a television writer — Shabaash India, Sa Re Ga Ma Pa, Indian Idol, Dance India Dance, Just Dance, Jhalak Dikhhla Jaa, Amul MasterChef, Dil Deke Dekho — and as one of Indian television's best-known acting coaches.

His coaching firm JUST ACT (later Rolexplore), co-conducted at one stage with casting director Mukesh Chhabra, has trained Pratik Gandhi (for Scam 1992), Jackky Bhagnani, Hrithik Roshan, Ayushmann Khurrana, Pranutan Bahl, Chef Vikas Khanna, Ranveer Brar, Javed Ali, Amaal Malik, Kritika Kamra, and many others. As acting coach and creative director he has also worked on Zee TV's India's Best Dramebaaz, India's Best Cinestars Ki Khoj, and Colors TV's Entertainment Ki Raat. He survived a serious 2008 Mumbai local-train fall before returning to the work.

His breakout as an actor came in 2020 as Ashwin Mehta — Harshad's brother — in Hansal Mehta's Scam 1992: The Harshad Mehta Story (SonyLIV), winning the Gujarati Mid-Day Award for Most Versatile Actor. He went on to play Aman Tokas in Love Hostel (ZEE5, 2022) opposite Vikrant Massey, Dr. Dhiren Kalita in Shadow Assassins (2022), the lead role in Aye Zindagi (2022), Mr. Raza in the short film Parchaaiyaan (2023), Somu Tyagi in Anil Sharma's Vanvaas (2024), and a double-lead role in Bicycle Thief (2025). On Sony SAB he plays the manipulative Patola businessman Viren Setalvad in the long-running Pushpa Impossible. In 2025 he was Zulfikar Ali Bhutto in Netflix's Saare Jahan Se Accha: The Silent Guardians, and in 2026 he plays Jainesh Patel in Netflix's Taskaree. His Gujarati lead Inspector Ranjeet Chauhan in OHO's Aazaad (2022) won him a dedicated regional following.

With Ideas Unlimited Productions he is part of the ensemble of Manoj Shah's Gujarati anthology Third Bell at NCPA Mumbai. He continues to work the Mumbai Gujarati and Hindi stage circuit including Lagan Magan and the upcoming Pandit Sukhlaal. He is married to Urvashi Kher (since 2 February 2006) and has two children, Shiv and Dhriti.