Fairfax County schools deputy superintendent Richard Moniuszko will retire in January to join the George Mason University faculty as a full-time education professor, he said in an interview Thursday.

Moniuszko, who joined the school system in May 2006, said he will spend the next six months assisting Karen Garza in her transition as the new superintendent.

“I have always wanted to teach at the collegiate level, and this was the perfect opportunity,” said Moniuszko, who turns 63 next month. “Mason is a progressive school with a tradition of innovation.”

Since May, Moniuszko has served as the interim superintendent after Jack Dale underwent emergency cardiovascular surgery. On July 1, Garza succeeded Dale, ending his nine-year term as the Fairfax schools chief.

Moniuszko served as the second-in-command in Fairfax County for the bulk of Dale’s tenure, helping to lead one of the country’s largest school systems and its 181,500 students.

He helped run the daily operations of the school district and acted as Dale’s “backup quarterback,” he said, stepping in as Dale’s surrogate for high-level meetings in the administration and events in the community.

“Being in the deputy job, you got to know the whole playbook,” Moniuszko said, noting that he was familiar with all aspects of the division, including special education, the facilities, transportation issues and advising school leaders.

Moniuszko said that he spent the majority of his time as a problem solver for the division, helping to lead task forces that studied discipline policies and dipping graduation rates.

A Baltimore native, Moniuszko is a graduate of the University of Virginia and earned his doctorate from the University of South Carolina.

He began his educational career as a school psychologist in South Carolina. He later served in the Charlotte-Mecklenburg school district and as deputy superintendent in Columbia, S.C., before moving to Fairfax. In Columbia, Moniuszko oversaw an effort that doubled enrollment in Advanced Placement courses and helped create a program that offered college-level classes to high school students.

As an associate professor at the George Mason college of education, Moniuszko will teach two or three graduate-level classes during the spring semester. He said his classes will focus on educational leadership and likely attract future principals and superintendents. He said he’s also eager to do some research, including studying what factors can lead to turning around low-performing schools.

“I have mixed feelings about leaving because I’ve loved FCPS,” Moniuszko said. “But it’s time.”