Agrawal, chief executive of Rational FX and online money transfer platform Xenday, was named to the position by London mayor Sadiq Khan earlier today.
Khan has tasked Agrawal with protecting jobs and growth while trade negotiations with the European Union and other countries take place.
Having run my own global businesses, I know how important it is that London remains welcoming to European and international trade.
The Mayor and I are determined to build a coalition that ensures the needs of business and financial services are at the fore over the coming months of negotiations with the EU. My first priority will be to listen and engage with businesses, to hear their concerns and deliver reassurance.
The mayor is calling for Britain and London to remain part of the European single market, sentiments that echo comments made by business secretary Sajid Javid yesterday.
I’ve pledged to be the most business-friendly mayor that London has ever had, and it is now more vital than ever that we act robustly from City Hall to protect our economy from the current uncertainty.
London must stay in the single market and be given more powers to ensure we can remain competitive, in order to attract the global enterprise that London’s prosperity relies on.
Khan yesterday called for London to "take back control" of its own destiny in the aftermath of the EU referendum, demanding increased tax-raising powers and further command of public services.
These devolved powers would be necessary to protect the capital's economy, jobs and prosperity, Khan claimed, giving the capital more control over business and skills, housing and planning, transport, health and criminal justice.
The London mayor has relatively little say over how taxes are spent in the capital compared to international counterparts, controlling just seven per cent.
In New York the mayor's office distributes 50 per cent of taxes, while in Tokyo it's 70 per cent.
Yesterday business leaders and industry groups turned on the government over its apparent lack of contingency plans in the aftermath of the Brexit vote.
A petition calling on the mayor to declare London an independent city-state reached almost 200,000 signatures in a matter of days.
Agrawal founded RationalFX in 2005, four years after coming to London, and by last year it had transferred tr more than $5bn. In 2012 Agrawal appeared in the Sunday Times Rich List with a £90m fortune.
The deputy mayor for business and enterprise position was last held by Kit Malthouse under former mayor Boris Johnson. Malthouse stood down in March 2015, and the job was then shared between a number of deputy mayors and senior advisors for the remainder Johnson's term.