In a statement, Warren said that Mnuchin was involved in the worst lending practices that led to the financial crisis during his time as head of mortgage lending at Goldman Sachs.
"Steve Mnuchin is the Forrest Gump of the financial crisis - he managed to participate in all the worst practices on Wall Street," said Warren in a statement according to Politico's Ben White.
"He spent two decades at Goldman Sachs helping the bank peddle the same kind of mortgage products that blew up the economy and sucked down billions in taxpayer bailout money before he moved on to run a bank that was infamous for aggressively foreclosing on families."
Mnuchin worked at Goldman Sachs for 17 years and left the bank in 2002. During his time he oversaw the mortgage lending department as it delved into such products as credit default swaps and collateralized debt obligations.
Since then, he founded his own private equity firm and the firm, Dune Capital Management, purchased distressed mortgage lender IndyMac in 2009, which was then renamed OneWest. The firm and Mnuchin have been accused of unfair lending practices including discriminating against minority borrowers and aggressive foreclosures.
"His selection as Treasury Secretary should send shivers down the spine of every American who got hit hard by the financial crisis, and is the latest sign that Donald Trump has no intention of draining the swamp and every intention of running Washington to benefit himself and his rich buddies," said the statement from Warren.