Sekou Biddle, a former member of the D.C. State Board of Education and the D.C. Council, said Friday he is challenging D.C. Council member Vincent B. Orange in the April Democratic primary, setting up a rematch after Orange defeated Biddle in a special election six months ago.

Biddle, who sat on the council from January through April, said he wants to regain the at-large seat he held because he’s heard from hundreds of city voters who “have shared their disappointment and even disgust with the quality of the public debate and public decision making.”

“On the one hand, we work long and hard to assert our legitimate claim to full home rule and statehood,” said Biddle, who announced his candidacy in front of the KIPP charter school in Ward 7. “On the other hand, we embarrass ourselves with sloppy decisions, unclear priorities and political mischief.”

In an interview after Biddle’s announcement, Orange said he looked forward to a “good, clean and very provocative campaign.”

“I believe I am the fresh start and new deal for the District of Columbia,” said Orange, adding that he has been focusing on trying to boost residents’ quality of life.

To comply with new federal guidelines for the timely mailing of absentee ballots to service members overseas, the District is moving up its party primaries from September to April. Primaries for wards 2, 4, 7 and 8, as well as delegate and shadow representative, will also occur April 3, 2012 — the same day as the city’s presidential primary.

But the at-large race will probably be the marquee contest on the ballot.

In January, the D.C. Democratic State Committee selected Biddle over Orange to temporarily fill the at-large seat left vacant by Kwame R. Brown’s election as chairman in 2010. But Biddle’s political ambitions collapsed in the April 26 special election, when he finished third, behind Orange and Republican Patrick Mara.

Biddle had been supported by both Brown and Mayor Vincent C. Gray (D), along with a majority of council members.

As investigations into alleged ethical missteps by Gray and Brown intensified last winter, Orange and Mara argued that Biddle was too connected to the city’s political establishment. Party leaders also criticized Biddle, who lost to Orange by nearly 10 percentage points, for running a haphazard, unfocused campaign.

Biddle, a former teacher, is now trying to position himself as a progressive, reform-minded alternative to Orange. He’s being supported by one of his former rivals in the special election, former Ward 1 advisory neighborhood commissioner Bryan Weaver. Weaver has a base of support among white liberals and younger voters.

In his announcement speech, Biddle accused Orange of raising most of his campaign funds from outside the District.

“One thing we are learning about D.C. politics is that money talks,” Biddle said. “When it comes from strange places, you have to ask who is talking.”

Orange, a moderate on the council who was an early champion of ethics reform legislation, countered that he’s less beholden to pressure from developers and special interests because many of his donors have no financial stake in the city.

“I am not beholden to them and can freely exercise my responsibilities and duties for the citizens without any undue influence,” Orange said.

Having run citywide three times, including unsuccessful campaigns for mayor and chairman, Orange will start his race against Biddle with higher name recognition and a broader fundraising base.

Orange, who lives in Ward 5, also maintains stronger ties to the city’s African American community, which accounts for the majority of the electorate in a Democratic primary.

But advisers to Biddle, who lives in Ward 4, note that Orange received only 29 percent of the vote in the April primary and predict he will struggle in what is so far a two-person race.

“We are not running against the Lion King here,” said Johnny Allem, a Biddle adviser.