Andrew Green was a corporate securities law associate in Hong Kong for Fried, Frank, Harris, Shriver & Jacobson at a time when he found himself increasingly involved in Democratic politics — fundraising, registering American voters and appearing for television and radio interviews.

Green’s corporate work and his political acumen would be soon put to a test on Capitol Hill as members of Congress began an ambitious and controversial Wall Street reform effort flowing from the financial crisis.

In 2009, Green snagged a post as legislative counsel in the office of Oregon Senator Jeff Merkley (D), a member of the Senate Committee on Banking, Housing and Urban Affairs, and he quickly became a leading adviser on banking regulation. “Given the economy was going off the cliff and folks were fleeing law firm land, I rolled the dice to see what I could land,” recalled Green, 35, whose portfolio included investment bank clients.

Merkley and Senator Carl Levin (D-Mich.) are credited with provisions in the Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010 that addressed limits on proprietary trading — the purchase or sale of financial instruments for a firm’s own account.

“Dodd-Frank was just an enormous piece of legislation — enormous in scope and enormous in its importance,” Green said. One of the driving questions, he said, was this: “What do we want our financial system to look like?”

Green was Merkley’s lead point person on the so-called Volcker Rule, a measure named after Paul Volcker, former chairman of the Federal Reserve. The rule, which addresses speculative trading, has drawn criticism from Wall Street. The law required a regulatory process, which is ongoing, to implement the rule.

In April, Levin and Merkley, leading a group of senators, urged Federal Reserve Chairman Ben Bernanke and other regulators to implement the Volcker Rule free of loopholes.

For Green, successfully navigating the Hill has meant bringing a wide set of skills to the table — where corporate lawyering meets litigation advocacy. “I was helping my boss analyze the facts as we understood them about what led to the financial crisis, doing the due diligence, and then helping to craft what the law should be,” he said. All with one goal in mind: to advance his senator’s vision. — Mike Scarcella