Virginia's top public schools official will retire at the end of the year, the Virginia Department of Education announced Monday.

Steven R. Staples, who was appointed as the state superintendent of public instruction by Gov. Terry McAuliffe in 2014, is scheduled to depart at the end of the year. His retirement is effective Jan. 1.

"It has been an honor and a privilege to serve in this capacity, and I will be forever grateful to so many for their advice, encouragement and support during my time in this post," Staples, 63, told Virginia Department of Education staff in an email.

In a conference call Monday, Staples said he's retiring to spend more time with family. He decided against requesting a reappointment from the next administration, he said, because he's doubtful he could commit the time.

In a news release, the Virginia Department of Education credited Staples with helping reduce standardized testing and for supporting the state Board of Education's efforts to redesign accreditation standards. Final approval from the board on the revised regulations is scheduled for November.

"I believe we have corrected an overemphasis on standardized testing while maintaining accountability for effective instruction and achievement," Staples, who stepped into office as a vocal champion of testing reform, said in the release.

During Staples' tenure, four-year high school graduation rates climbed above 90 percent.

He oversaw the state school system's expansion into computer-adaptive testing, which customizes assessments for students. Under that form of testing, a student's response to a question determines the difficulty of the next item, with a correct response leading to a more challenging question.

Under his guidance, schoolchildren were able to take tests on a greater variety of devices, including tablets.

State education officials and advocates, including Board of Education president Daniel Gecker, lauded Staples for his contributions. Gecker described the departing superintendent's experience as an educator and administrator as invaluable — Staples was a teacher and principal before becoming superintendent of York County public schools in 1991.

"He helped the board understand how policy impacts practice and the importance of listening to all stakeholders," Gecker said in the news release.

One of the toughest parts of the job, Staples said, was shepherding policy that would prove beneficial for students across the state.

"This job has given me a new perspective on the diversity across the state and trying to reconcile that diversity with state level policy that produces positive results for all," he said.

In a statement, Chris Minnich, executive director for the Council of Chief State School Officers, said Staples displayed a commitment to bettering education for students from all walks of life.

"Steve Staples has championed the importance of continuous improvement for all schools, believing that even high-performing schools must continue to strive for excellence for all students," he said.

Staples acknowledged much work remains as he prepares to leave office and cited teacher shortages and diversity in hiring as among the most critical issues facing the next state superintendent.

"Frankly, all of our work is for nothing if we can't get qualified teachers in our classrooms," he said.

Before serving as superintendent, Staples was the ­executive director of the Virginia Association of School Superintendents and a faculty member in the College of William & Mary's School of Education. He began his teaching career in 1976 in Prince George County.

Staples received his bachelor's and master's degrees from William & Mary and a doctorate from Virginia Tech, according to the state education department.

Staples doesn't have specific plans for retirement but said it would be "difficult to get away from education, entirely."