Okafor played just once at this summer's World Cup, a substitute appearance in the round-of-32 win over Algeria, despite arriving in the squad on the back of four goals in his final four games of the season for Leeds.
He remained an unused substitute as Switzerland reached the semi-finals for the first time since 1954, eventually losing 3-1 to Argentina after extra time. In a lengthy statement posted on Instagram, the winger announced he was stepping back from the national team "until further notice."
"Dear fans, these lines are the hardest I have written in my career so far. After careful consideration, I have decided to step down from the Swiss national team until further notice," Okafor wrote.
"This decision is extremely difficult for me, but I want to and must state it now. There was never anything greater for me than playing for Switzerland. Every time I have worn this jersey, I have tried to leave my heart on the pitch."
The decision follows a rift with Yakin that had appeared resolved earlier this year, when the head coach travelled to England specifically to meet Okafor after the winger had criticised Swiss bosses for failing to communicate with him during a previous 16-month exile from the squad.
"A year after the European Championship, Murat Yakin came to England with members of the coaching staff specifically to have a clarifying conversation with me. It was a very appreciative and good conversation. We were able to look forward and clear up misunderstandings. I was grateful to Murat Yakin for that," he said, adding that he had travelled to the World Cup "with a good feeling, full of motivation."
Okafor was careful to stress that his decision was not about playing time, despite anticipating that reaction from some observers.
"One thing up front: I know that some will think again now: 'Oh, Okafor again, he's just offended because he hardly played.' But again: my decision has nothing to do with my playing minutes," he said. "Things happened that hit me deeply. Trust was broken. Promises were not kept. And when I was allowed to play against Algeria, even small mistakes far away from our goal were reacted to in a way that hit me deeply."
The Leeds United forward was careful to praise Yakin's results while explaining why he could not continue under him.
"Murat Yakin is doing a great job and has achieved historic things with Switzerland. The success proves him and his work right. And of course, I don't want any special treatment from him. Only mutual respect and trust, but I do not see this foundation for the coming years," he said, closing with a message to team-mates he described as friends.
"I sincerely wish the team only the best. I am grateful to Switzerland for everything I was able to experience. Playing for this country was and remains something very special."
The Swiss Football Association confirmed the news in a brief statement.
"Noah personally informed us today that he will no longer be playing for the national team for the time being. We respect his decision and wish him good luck and success with his club," the federation said. Okafor has featured in all of Leeds' matches so far this season.