After doing his Masters he joined J M Financial Limited in 1983-1984 in Mumbai as a management trainee/intern in Portfolio Management and securities trading on the Indian Stock Market under Mr. Mahendra Kampani, Vice Chairman, J M Financial Limited. He was just 24 years then. After two years with J M Financial Limited, when Siddhartha returned to Bangalore, his Father gave him money to start a Business of his choice. Siddhartha bought a stock market card for Rs 30,000, along with a company called Sivan Securities, which was renamed in 2000 as Way2wealth Securities Ltd with vision to set "new standards in the Retail financial services in India". Its venture capital division came to be known as Global Technology Ventures (GTV) as well as a site in the city in 1984 and turned it into a highly successful investment banking and stock broking company.

He started his coffee trading company ABC in 1993, with a Rs 60 million turnover. His company grew gradually. He bought an ailing coffee curing unit in Hassan for Rs 40 million and turned it around. Now, his company has a curing capacity of 75,000 tonnes, which is the largest in the country.

He was the first Entrepreneur in Karnataka to set up a café in 1996 (Café Coffee Day, a chain of youth hangout coffee parlors). Now, he has 1550 Coffee Day Cafes in India. Siddhartha also hopes to win the contract to take his chain to all the airports of Karnataka and then to the rest of the country. His cyber cafes attract at least 40,000 to 50,000 visitors a week.

Siddhartha also founded Global Technology Ventures Ltd. in 2000, a company that identifies, invests and mentors Indian companies engaged in cutting edge technologies. Currently, he also holds board seats in GTV, Mindtree, Liqwid Krystal, Way2Wealth and Ittiam. GTV has now set up a global Technology village on a 59-acre (240,000 m)technology incubator park in Bangalore, which will provide office space, communication links, recreational facilities and even a commercial centre. GTV was valued by BankAm at $100 million last year, and is expected to have doubled its valuation this year. It is poised to grow on the lines of SoftBank of Japan.

Siddhartha was awarded the Entrepreneur of the year title in 2003 by The Economic Times for "crafting a successful pan Indian brand for a commodity Business and giving Indian consumers a new lifestyle experience that is within reach of the Common man".

Way2Wealth stepped into real-estate Business under the name of Way2Wealth Realty Advisors Pvt. Ltd., in year 2010. This arm of the company offers a consulting and broking services in the Real Estate arena to both Corporate as well as Individual customers.

Amalgamated Bean Coffee Trading Company Ltd. today is the largest exporter of green coffee from India and perhaps one of the two fully integrated coffee companies of Asia, involved in all sectors of coffee from plantations to Retailing to exports. Coffee Day Group today is the only fully integrated and the largest coffee conglomerate in India and is credited with creating the "coffee revolution" in India — acknowledged by the Coffee Board of India Amalgamated Bean Coffee Trading Company Ltd.. From a handful of cafés in six cities in the first five years, Café Coffee Day has become India's largest and premier Retail chain of cafes with 1,423 cafes in 209 cities/towns.

Owner of the Cafe Coffee Day chain, V G Siddhartha, found himself amidst a tax evasion on 21st September 2017. A tax raid was conducted at over 20 locations in Mumbai, Bengaluru, Chennai and Chikmagalur by senior officers of Income Tax Department of Karnataka and Goa regions.

V G Siddhartha has taken 1.85 million hectares of Amazonian forestland on a 30-year lease from the Republic of Guyana in South America to start a furniture Business in India. The idea is to transport cut logs on chartered ships from the Guyanese capital Georgetown to the Mangalore Port and then carry them via road to the Coffee Day Group’s furniture plant in Chikmagalur. The Amazonian hard wood varieties coming to Indian shores through this route will include Greenheart, Purpleheart, Wallaba and Bullet Wood. The royalty that Siddhartha will pay the Guyanese government is not clear. Siddhartha declined to comment on the matter. A couple of years ago, the Coffee Day Group had started a furniture unit to capitalize on the huge depository of full-grown silver oak, teak wood, rose wood and mahogany trees grown in its 15,000-acres of coffee gardens in Chikmagalur. The unit designs multi-purpose furniture for home, kitchen, office, hotels and Retail outlets. It also manufactures all kinds of plywood, wood boards, panel sheets and beadings, making use of the wood waste and saw powder. But it has so far remained mostly as a captive unit, serving the requirements of the Group’s coffee outlets and the resorts under the brand name Serai.