Calvin Duncan arrived at the courthouse in New Orleans at 7:50 a.m. on Monday, his first day as the city’s elected criminal court clerk. His predecessor showed him where evidence was stored, and his new staff explained the filing system for case records.

At 11:11 a.m., he left the courthouse, unsure whether he still had a job.

Mr. Duncan, a Democrat, won election in November and was set to take office on Monday. But in recent weeks, things became complicated: The Republican state legislature passed a law eliminating his new job as part of a broader effort to shrink the judicial system in New Orleans. He sued, and on Sunday, a lower court temporarily blocked the law from going into effect, finding that it was likely unconstitutional.

The U.S. Court of Appeals for the Fifth Circuit halted the lower court’s ruling on Monday morning, prompting Mr. Duncan’s exit just hours after he showed up for work.

“We thought that it would be best for us,” Mr. Duncan said, “to leave gracefully and with the hope that the court would resolve it.”

Over the past year, Mr. Duncan, 63, who spent 28 years in prison for murder before being exonerated and becoming a lawyer, has brought an unusual level of attention to an elected office that rarely draws any.

His campaign, which started as a long shot, gained notice after the incumbent he challenged spread false claims that he had never been exonerated in the murder. He won in November by a significant margin. But in the weeks before he was set to begin, state lawmakers targeted his office as part of a plan that also involved reducing the number of judges in New Orleans.

On Friday, Gov. Jeff Landry of Louisiana, a Republican, signed legislation that folded the criminal clerk’s responsibilities into the office of the civil court clerk, a separate elected official.

But on Sunday, a few hours before the law was set to go into effect, a federal judge found that state lawmakers had likely exceeded their authority by abolishing an elected office, violating the U.S. and state constitutions. The order was temporary, a stopgap until more extensive arguments could be made.

The American Civil Liberties Union of Louisiana, which is representing Mr. Duncan, declared victory, saying the court had cleared the way for him to take office, at least for the time being. A crowd of supporters cheered as he entered the courthouse on Monday morning.

A few hours later, the appellate court halted the federal district judge’s order, issuing a stay while it weighed the state’s argument that the issue should rest with the Louisiana Supreme Court.

The twists and turns made for a lot of uncertainty.

According to Mr. Landry, the appellate ruling “means the law to consolidate the clerks of court is in effect.”

According to the A.C.L.U., “Calvin Duncan is clerk of the criminal court for Orleans Parish.”

The civil clerk, whose office would assume the criminal clerk’s duties under the law, did not immediately respond to a request for comment. But she has expressed concerns about her expanded portfolio.

“I did not ask for this, nor do I agree with the process,” the civil clerk, Chelsey Richard Napoleon, said in a statement on Friday after the governor signed the bill. She said her foremost priorities were running the May primaries in the city and ensuring a “stable transition” of records and evidence.

In an interview on Monday afternoon, Mr. Duncan acknowledged that the situation was head-spinning. But for now, he said, he was standing by.

“All this morning since midnight, I was the clerk of the criminal district court, because the office was back on the map,” Mr. Duncan said. “But then they got the stay. Now, I don’t exist anymore.”