WASHINGTON — Jared Kushner, President Trump’s son-in-law and senior adviser, has been granted his permanent security clearance, a person briefed on the matter said on Wednesday, ending a period of uncertainty that had fueled questions about whether Mr. Kushner was in peril in the special counsel investigation.
Mr. Kushner is a senior presidential aide with a prominent role in Middle East diplomacy. But his F.B.I. background checks dragged on for a year and became one of many political distractions for the White House. Even some inside the administration suspected that Mr. Kushner’s delay reflected legal problems on the horizon.
The permanent clearances make Mr. Kushner, who is married to Mr. Trump’s daughter Ivanka Trump, eligible to view some of the United States’ most closely guarded secrets, including the daily intelligence briefing that Mr. Trump receives and the delicate intelligence on the Israelis and the Palestinians that former diplomats said can be valuable in negotiations. Top-secret clearances are typically required for people viewing foreign intelligence or sitting in on high-level White House meetings.
White House officials were adamant that the lengthy process was not unusual for a government official who has a complicated financial history and many foreign contacts. But with the special counsel investigating some of Mr. Kushner’s meetings with Russian officials, it left open the question of whether investigators had uncovered evidence that made him a security threat.
The special counsel, Robert S. Mueller III, is investigating whether anyone around Mr. Trump conspired with the Russian government to help influence the outcome of the 2016 presidential election. Mr. Kushner’s meetings with the Russian ambassador, a Kremlin-connected lawyer and a prominent Russian banker have all attracted scrutiny.
The resolution of his clearances does not guarantee that Mr. Kushner faces no legal jeopardy. But Mark S. Zaid, a veteran Washington lawyer who handles security clearances, said it was highly unlikely that the special counsel would uncover evidence of improper foreign entanglements and not flag it for security officials.
“If I were Jared Kushner, I’d be sighing a breath of relief today,” Mr. Zaid said.
The special counsel’s investigation had not caused the delay, said Mr. Kushner’s lawyer, Abbe D. Lowell.
“With respect to the news about his clearances, as we stated before, his application was properly submitted, reviewed by numerous career officials and underwent the normal process,” Mr. Lowell said. “Having completed all of these processes, he’s looking forward to continuing to do the work the president has asked him to do.”
Mr. Kushner has outlasted some of his chief White House rivals, including Reince Priebus and Stephen K. Bannon. But his relationship with the current chief of staff, John F. Kelly, deteriorated from almost the very beginning. And Mr. Trump, who once considered Mr. Kushner a trusted adviser, continues to tell friends he wishes that Mr. Kushner and Ms. Trump would return to New York.
The clearance announcement will not drastically change Mr. Kushner’s ability to play peacemaker in the Middle East. Even without a top-secret clearance, he was able to attend meetings with Prime Minister Benjamin Netanyahu and other top Israeli officials.
A White House spokesman did not respond to a message seeking comment. Mr. Kushner’s clearances were approved by career officials after the completion of the F.B.I. background check, and the president was not involved in the process, according to the person briefed on the matter, who spoke on the condition of anonymity because clearance decisions are supposed to be secret.
Mr. Lowell said that Mr. Kushner has cooperated fully with the special counsel and met with Mr. Mueller’s investigators twice for many hours. “In each occasion, he answered all questions asked and did whatever he could to expedite the conclusion of the investigations,” Mr. Lowell said.
Mr. Kushner was among several White House officials who spent the first year of the administration working under provisional clearances, meaning he was allowed to view classified information while his F.B.I. background check was pending.
Those interim clearances became stand-ins for the larger Washington debate over links between members of the Trump campaign and Russian officials. Mr. Trump’s team steadfastly denied any such contacts, only to have journalists and investigators uncover one undisclosed meeting after another.
Mr. Kushner met during the campaign with a Russian lawyer who came to Trump Tower promising political dirt on Hillary Clinton. During the presidential transition, he met with the Russian ambassador, Sergey I. Kislyak, and the head of a Russian state-owned bank. But when he applied for a security clearance, Mr. Kushner did not disclose those meetings.
His lawyers said the application was filed inadvertently, while the form was still in progress. They said he did not conceal Russian contacts; he had not yet begun completing the section requiring him to disclose his foreign contacts. As a New York real estate developer and the point person for the presidential transition on many diplomatic issues, Mr. Kushner had many such contacts.
Mr. Kushner amended the form and was interviewed by Congress about his Russian contacts. “All of my actions were proper and occurred in the normal course of events of a very unique campaign,” Mr. Kushner said last July after speaking behind closed doors on Capitol Hill. “I did not collude with Russians, nor do I know of anyone in the campaign who did.”
Congressional Democrats, though, clamored for more information about Mr. Kushner’s clearances. In February, amid questions about an aide who kept his interim clearances despite accusations of domestic violence, the White House stripped Mr. Kushner and others of their provisional access to classified information.
That led only to new questions about Mr. Kushner’s relationship with Mr. Kelly and his future in the White House. In addition to his work on Israeli-Palestinian peace negotiations, Mr. Kushner acts as an intermediary with Mexico, is pushing for reforms to federal prisons and is working on revising the North American Free Trade Agreement.
Maggie Haberman contributed reporting from New York, and Mark Landler from Washington.