SALEM — Clyde Saiki is retiring after two tumultuous years as director of the Department of Human Services, the state’s largest agency.

In an email to staff Friday, Saiki said he will be succeeded by Fariborz Pakseresht, director of the Oregon Youth Authority since 2012.

The changeover takes effect Sept. 1, although Senate confirmation of Pakseresht’s appointment is required. Saiki will stay on in a limited role during the transition.

Saiki, 60, had previously worked at DHS for 23 years, rising to become its chief administrative officer and deputy director of operations before he took a similar position at the Department of Transportation in 2010.

He was Gov. Kate Brown’s choice in 2015 for director of the Department of Administrative Services — the budget and management agency for state government — after Michael Jordan resigned.

Brown then sent Saiki back to DHS in November 2015 following news reports about serious problems with the foster care system. He became permanent director in March 2016, and shortly afterward he fired two child welfare officials.

“In his three decades of service to the State of Oregon, Clyde has demonstrated exemplary leadership at every agency,” Brown said in a statement. “I would like to thank him for his contributions to DHS and for his continued leadership through the summer to ensure a smooth transition when Fariborz takes the helm on Sept. 1.”

Deputy Director Joe O’Leary will lead the youth authority on an interim basis.

“Before the new director arrives, we need to finish the legislative session and begin the important work of implementing the 2017-19 legislatively approved budget — with investments and reductions still to be determined,” Saiki said in the email. “There is much work to do between now and September, and while I know an adjustment to a new director will take time I hope that we can continue to work full steam ahead.”

Even after the Oregon Health Authority split off in 2011, DHS still has the most employees of any state agency — 7,900 full-time equivalent positions.

The agency, created in 1971, has continued to struggle to resolve the child welfare problems.

In addition to child welfare, the agency oversees services for older people and people with disabilities, and programs to make people more self-sufficient. Its current two-year, $10.2 billion budget — $2.7 billion of it from the tax-supported general fund — is second only to that of the state health agency.

But the agency’s budget faces paring with a projected revenue shortfall of $1.6 billion in the 2017-19 budget cycle — and there is uncertainty about how much federal aid it will receive.

“I know Fariborz very well, and I believe he is a great choice to lead the important work you all do every day,” Saiki said. “He has history working at DHS and understands the importance of our programs in so many Oregonians’ lives.”