James D. Schultz, a senior associate White House counsel for President Trump until last week, has returned to the Philadelphia-based law firm Cozen O'Connor as chairman of its government and regulatory practice.

Schultz, 45, a former general counsel of the commonwealth, was appointed a special assistant to Trump shortly after the inauguration in January. His portfolio in the counsel's office included compliance with ethics regulations — making sure presidential appointees across the government reported their financial holdings, divested themselves when required, and avoided conflicts of interest.

The Trump administration has been bedeviled by a series of ethics controversies, starting with the president's decision not to divest himself of his business interests, which is customary but not required, and incomplete financial disclosures by son-in-law and senior adviser Jared Kushner and other top officials.

Schultz said he did not resign because of those problems, but had planned from the beginning to return to private practice after about a year and told White House Counsel Don McGahn so. Schultz's family had remained in Philadelphia, which he said was "a strain" at times.

"I was honored to serve, and it was a great opportunity, but I wanted to stay long enough to help get things up and running," he said.

Some of the criticism over disclosure, Shultz said, was motivated by political opponents in the bureaucracy and non-profit advocacy groups. He noted that the administration has brought in a large number of successful business people who have complicated financial situations, and said that disclosure forms are often amended. "It's an onerous process," Schultz said.

In the White House, Schultz also handled infrastructure and government contracting issues, and helped in the vetting of Trump nominees for U.S. attorney and federal judge positions.

"The job and the people I worked with were as interesting as could be, and it was rewarding to serve," Schultz said in an interview. "It was amazing walking those halls, with all the history there. The last day was a tough one."

Schultz had barely begun building a list of clients as a Cozen O'Connor partner last year when he joined the legal team working for Trump at the Republican National Convention, advising on floor operations and deliberations over the GOP platform and rules. He also was an adviser in the transition office.

Schultz served as Pennsylvania's top lawyer under Republican Gov. Tom Corbett, from July 2012 through November 2014. In Harrisburg, he provided legal advice to the governor and the executive staff, and supervised about 500 lawyers who represented 36 departments as well as independent state boards and commissions.

An aide to federal prosecutor Patrick Meehan, now a U.S. House member from the suburban Seventh Congressional District, Schultz had worked at Cozen O'Connor as a litigator from 2008 until 2011.

"As we continue to expand our services in Washington, D.C., and across the country, Jim's experience and expertise will be invaluable to our clients," said Michael J. Heller, president and CEO of the law firm.

Schultz, a native of Galloway Township, N.J., received his bachelor's degree in 1995 from Temple University, where he was an offensive lineman for the Owls football team. He got his law degree in 1998 from Widener University School of Law.

This story was updated to clarify the reason for Schultz's move.