The 30-year-old said that after four years leading the AUF, the youth wing of Norway's Labour Party, it was time to find a new role.
"It has been an exciting and tough period, and now it feels right to invent something new," Pedersen told Norway's NRK newswire. He said he would be "very happy" to do politics, but was also considering applying for positions in in business.
In an interview with the Dagbladet newspaper, Pedersen spoke about what had happened in July 2011, when he and a handful of other AUF members left the island of Utøya on the ferry MS Thorbjørn, leaving those remaining with no boat on which to escape.
"One has no answer as to what is the right thing to do during such an attack," he said. "I was 'blind'. I chose to listen to what my closest colleagues thought about how I should run. Then I listened to what the police said," he told the paper.
He described the aftermath of the 22 July attack as "intense".
"It has been very painful to lead an organization that was hit by a massive terrorist attack, and it has cost me a lot personally. I have lost many friends, while it has also been rewarding to take AUF ahead after 22 July."