"I'll be coming back to work after March 31," Jimmie Åkesson said during the taping of a television talk show to be aired Friday on Swedish public broadcaster SVT, excerpts of which were published on SVT's website.
Åkesson has lifted Sweden's far-right party from obscurity to a serious parliamentary force, with the 35-year-old seeking to position himself as a kinder, gentler sort of anti-immigration leader.
The Sweden Democrats more than doubled their support to 12.9 percent of the vote in Sweden's general elections in September, becoming the third-biggest party in parliament.
A month later Åkesson, who has led the party since 2005, announced he had been put on sick leave by his doctors because he was burned out due to his heavy workload and stress.
Sources had suggested earlier on Monday that Åkesson was planning a return to politics, which he confirmed late on Monday night in an interview with Fredrik Skavlan.
He told the Norwegian talk show host, who is hugely popular in Sweden, that his return will happen in stages, with him initially participating in "work training".
"I guess that's how you get back after this kind of illness," he said.
Mattias Karlsson, the leader of the party's parliamentary group, has filled in for Åkesson during his absence and the party has maintained its support level in the polls under his leadership.
Some had even suggested that Karlsson could take over the helm of the party permanently.
In January, Sweden's Expressen newspaper published parts of an email written by Åkesson in which he said that he had full confidence in Karlsson.
He added that he and Karlsson had "worked closely together for over 15 years" and said that any suggestions about rivalry between them had been "completely plucked out of the air".
The party remains angry that Sweden's Social Democrat Prime Minister Stefan Löfven scrapped plans to call a snap election in March, after reaching a budget compromise known as the December Agreement with the country's centre-right Alliance parties.