[1][4] Early in his career, in 1985, Thapar first worked in KCTB 's manufacturing plant in Yamunanagar and then he moved to Andhra Pradesh Rayons, where he fixed the business relationship between the company and Grasim Industries.

[1] In 1997, Thapar had responsibility to turn around the BILT's chemical division, which was suffering losses due to management-labour conflicts and shortage of water and power.

[6][1] Gautam showed profits within a year, by scrapping the company's expansion plans, selling off a few assets and trying to resolve labour concerns.

[1] On 29 August 2019, Thapar was sacked as Chairman of CG Power and Industrial Solutions with immediate effect after an investigation that unearthed a multi crore financial scam at the firm.

Thapar was arrested by authorities under the Prevention of Money Laundering Act (PMLA) on August 3 following raids that were conducted by the ED in Mumbai and Delhi according to a report by PTI.

[15] In August 2024, the ED, as part of their investigations into the PMLA case against Thapar, attached Rs 678 core worth of assets of the Avantha Group.

[16] In September 2024, the ED, as part of the probe into the alleged bank fraud, attached 24 properties worth Rs 78 crore of a company beneficially owned by Thapar.