In 1969, he helped set up the Tata Consultancy Services, at the request of J. R. D. Tata, the group chairman, after Tata Electric company installed a computer system to control the power lines between Mumbai and Pune, making it the third utility company in the world to install such a system. After internally serving a few of the Tata Group companies, TCS went on to sign its first contract with Burroughs Corporation for software services, in 1972. He would go on to become the company's first CEO and also serve as its deputy chairman. He would lead the company for the next three decades before stepping down as the CEO in 1996. The company is the largest Indian IT services company by market capitalization and the most valuable company within the Tata group as of 2020. He was also associated with other companies within the Tata Group including being on the board of Tata Sons, Tata Industries, Tata Unisys, Tata Electric Company, Tata Honeywell, and Tata Technologies Singapore. He had also been the chairman of Tata Elxsi India, and WTI Advanced Technologies. Outside of the Tata Group, he has been a director on the board of Airline Software Development Consultancy India, Airline Financial Support Services India, Abacus Distribution Systems, and Triveni Engineering Works. He was president and chairman of Indian IT services advocacy body, NASSCOM, between 1995 and 1996. In this role, and later as a part of the body's executive committee, he helped shape global partnerships and showcase opportunities to deliver IT services from India. He was also associated with professional organizations like the Computer Society of India, the Institute of Electrical and Electronics Engineers New York, the Institution of Electrical Engineers, the Indian National Academy of Engineering, and the Institute of Management Consultants of India. Kohli also played an important role in the advancement of technical education in the country. In 1959, under a request from P. K. Kelkar, the founding director of the Indian Institute of Technology Kanpur, he helped with the faculty selection and recruitment. He was also associated with the College of Engineering, Pune, by pushing for the institute to be granted autonomous institute status, and stayed on as the chairman of the Board of Governors of the institute. He held executive and leadership roles in professional societies, including being on the board of directors of the Institute of Electrical and Electronics Engineers (IEEE)