Jain was born on 7 January 1963 in Jaipur, India, and his father was a career civil servant[9][3] who served in the Indian Audit and Accounts Service.

[10] He studied at Shri Ram College of Commerce at the University of Delhi and earned Bachelor of Arts in economics in 1983.

[11] He then moved to the U.S. at the age of 19,[12][13] and in 1985 he received a Master of Business Administration in finance from the Isenberg School of Management at the University of Massachusetts Amherst,[14][11] where he was a member of Beta Gamma Sigma.

[19][10][18] Jain joined Deutsche Bank in June 1995 to head a combined group which marketed fixed-income derivatives to large investors and hedge funds.

[21][22] In February 1997, he was named head of Deutsche Bank's newly formed Global Institutional Client Group,[23][24] and expanded fixed income into foreign exchange and credit derivatives.

[26][27][22] When Mitchell died in a plane crash in December 2000, Jain succeeded him as head of Global Markets in early 2001.

[34][3][12] Cohrs retired in 2010, and Jain became head of the entire Corporate and Investment Bank,[25] overseeing global sales and trading operations that included bonds, commodities, emerging markets, equities, foreign exchange, money markets, credit derivatives, and interest-rate trading.

[13] He had already been appointed to Deutsche Bank's 12-member Group Executive Committee, newly created by Ackermann,[37] in 2002,[38] and to its Management Board (Vorstand) in 2009.

[39][40][38] In July 2011, Jain was appointed co-CEO of Deutsche Bank, along with native German Jürgen Fitschen, effective 1 June 2012.

[55] Subsequent regulatory fines included $2.5 billion in penalties in April 2015 to four regulators in the U.S. and UK over claims that Deutsche Bank traders had manipulated key interest-rate benchmarks such as the London Interbank Offered Rate (Libor) between 2005 and 2011.

[71][70][60][53][64] Seeing this as a loss of shareholder confidence,[34][28] and facing criticism from employees over job cuts and closures in the restructuring plan,[72] and in the wake of the April 2015 Libor fine and report plus a subsequent $55 million SEC fine and an internal Russian money-laundering probe,[10][66] Jain and Fitschen announced their resignation on 7 June 2015.

[75][76][77] In January 2017, he became president of Cantor Fitzgerald, a mid-sized, private New York–based firm, headed by Howard Lutnick, which offers investment banking and other financial services.

[80] He was hired at Cantor Fitzgerald to help expand fixed-income and equities trading as well as prime brokerage,[5][81] and he worked alongside Lutnick and directed strategy, vision, and operational foundation across the firm's businesses.