Steven T. Miller, the former acting commissioner in charge of the Internal Revenue Service who left the agency last year amid revelations of improper screening of tax-exempt applications, has joined the tax advisory firm alliantgroup as national director of tax.

Miller became acting commissioner of the IRS in late 2012 after the departure of Douglas Shulman. He will be joining another former IRS commissioner at alliantgroup, Mark W. Everson, who left the IRS in 2007. The Senate recently confirmed a new IRS commissioner, John Koskinen, who was sworn in Monday by Treasury Secretary Jack Lew.

In his new role at alliantgroup, he will be leading the firm’s Washington National Office while expanding the scope of the firm’s Tax Controversy Services practice and helping clients deal with federal, state and international tax matters.

“I am excited to join such a great and energetic team,” Miller said in a statement. “I look forward to helping American businesses comply with the Tax Code and successfully navigate their relationships with tax agencies.”

Miller held a number of top management roles at the IRS during his 25-year career at the agency. As former deputy commissioner for services and enforcement at the IRS, Miller led enforcement and service activity at the agency. He also served as the commissioner of the IRS’s Large and Midsize Business Division, overseeing audits of large taxpayers and the IRS programs relating to offshore tax compliance and international tax law enforcement. As commissioner of the Tax Exempt and Government Entities Division, Miller supervised IRS oversight of governments, tax exempt entities and retirement programs.

His former IRS colleague welcomed him to his new job. “I am pleased to welcome Steve Miller to alliantgroup,” said Everson, who is now a vice chairman at alliantgroup. “Steve's broad experience at the service—including oversight of critical initiatives like implementation of the Affordable Care Act and efforts to combat identity theft—can only help the CPAs and clients we work with across the country.”