Ken Kies, the Treasury Department’s top tax policy official who has also been serving as acting chief counsel of the IRS, is expected to leave the federal government.

His departure would open another significant hole in IRS leadership. Neither of the two senior IRS leadership positions that require presidential appointment and Senate confirmation—the commissioner and the chief counsel—is currently held by a confirmed official.

Kies was confirmed by the Senate in June 2025 as Treasury’s assistant secretary for tax policy. In that role, he has overseen the development of federal tax policy and the implementation of tax legislation, including the One Big Beautiful Bill Act (OBBBA).

Kies brought decades of Washington tax experience to the administration. Before joining Treasury, he was managing director of the Federal Policy Group, a Washington lobbying firm whose clients included major corporations and trade associations. Earlier, he spent about a decade at Congress’s nonpartisan Joint Committee on Taxation, including three years as chief of staff.

Kies was formally designated acting chief counsel in November. His dual assignment gave him an unusually wide role in the tax system. At Treasury, he helped oversee tax regulations and other administrative guidance. As acting chief counsel, he led the lawyers advising the IRS on how tax laws should be interpreted and enforced.

It is not clear exactly when Kies will leave. Several longtime IRS insiders expressed surprise at the news.

What The IRS Chief Counsel Does

The IRS chief counsel is the agency’s top legal officer and advises the IRS commissioner on the interpretation, administration, and enforcement of federal tax laws.

The position dates back to 1866. Under the IRS Restructuring and Reform Act of 1998, the chief counsel reports to both the IRS commissioner and the Treasury general counsel.

Attorneys in the Chief Counsel’s Office serve as lawyers for the IRS. They provide guidance on how federal tax laws should be interpreted, advise IRS employees, help develop regulations and other published guidance, and represent the government in Tax Court and other tax litigation.

That makes the position especially important when Congress has enacted major changes to the tax code, like OBBBA. Decisions about how statutory language should be interpreted and implemented can affect billions of dollars in taxes and determine how new........

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