Fairfax County supervisor Michael Frey said Tuesday he will not seek a seventh term in November, a surprise announcement by the Sully District’s first and only supervisor that could change the political dynamics of the county board.

After 24 years in office that began when his district was created in 1990, “it just seemed like time,” said Frey, 58, who is one of three Republicans on the 10-member county board.

“There’s nothing pressing that I want to get done,” he said. “There are always more things that you would like to do. . . . But there is nothing real huge, so it seemed like a good time.”

Frey’s announcement opens a political vacuum in a wealthy but historically moderate area of Fairfax County that is increasing in density, with new apartments and townhouses sprouting in Chantilly, Centreville and surrounding areas.

Almost immediately, Brian Schoeneman — the Republican secretary of the county’s electoral board — announced his candidacy for Frey’s seat, a decision made just one week after Schoeneman moved into the district from his previous home five miles away.

In this file photo from 2010, Fairfax County Sully District Supervisor, Michael Frey (R) listens at a public meeting. (Greg E. Mathieson, Sr./(C) 2010 Greg E. Mathieson / MAI)

“This was the craziest thing; We moved here last week, and Mike tells me two days later that he’s planning to retire,” said Schoeneman, 37, who ran unsuccessfully for state delegate in 2011 and also announced Tuesday that he’s stepping down from the county electoral board.

“What I would say to people who want to make an issue of that, is where I used to live in the county was part of the Sully District back in the day,” Schoeneman said. “And, all the issues are the same.”

So far, no Democrat has announced a candidacy. However, local school board member Kathy Smith is expected to toss her hat into the ring and used Frey’s news to suggest to voters that she’s capable of stepping into his role.

“Michael Frey has been an outstanding member of the Board of Supervisors,” Smith said in a statement. “I’ve enjoyed working closely with him as the Sully representative for 13 years.”

The Sully District was created in 1990 after more people began moving to the northwestern portion of Fairfax County.

Frey was elected into his office after serving as an aide for 14 years to several other county officials, among them former county board chairman John S. “Jack” Herrity.

Frey’s local legacy includes getting his head shaved every year to show support for children’s cancer research. Frey was also instrumental in expanding the Centreville historic district and in creating an immigrant day labor center in that area’s shopping center in 2010 that continues to operate.

Some aspects of the office, he said, “got harder and harder” as time passed — particularly the early morning meetings on issues outside his district that often mean long commutes.

“Living in Centreville, with no way to get to Tysons but the I-66; that’s a horrifying thought,” Frey said.