From 1992 until 2002, he was an assistant United States attorney in the Eastern District of New York, where he prosecuted cases involving "white-collar fraud, narcotics trafficking, labor racketeering, public corruption, and money laundering."

[3] Ramos came under ethical scrutiny for allegedly violating the Judicial Code of Conduct by failing to disclose financial conflicts of interests in matters he presided over.

In September 2021, the Wall Street Journal published an article reporting that more than 131 federal judges had violated their ethical obligations by presiding over matters where they had a financial interest.

Investors had sued major banks, including Barclays and HSBC, accusing them of rigging the foreign bond market.

He subsequently recused himself from the matter, which was taken over by Judge Valerie E. Caproni; she reconsidered the dismissal of the investors' complaint against the banks and allowed the case to proceed.