Siv Jensen during the party's annual conference on Friday. Vegard Grøtt / NTB scanpix
To waves of applause from party activists, Jensen boasted that the party had cut seven billion kroner in taxes, started work on tightening immigration policy, and proven itself "sensible and responsible" in government.
"For decade after decade, we have been laughed at and seen as a disturbing element," she told the packed conference room. "The other parties have claimed there would be chaos if we were to get control."
The party's record in office had disproved this once and for all, she said.
"Each day the Progress Party is in government, we are nullifying the skepticism they have had against this party for 40 years."
She criticized Jonas Gahr Støre, the man soon to replace Jens Stoltenberg at the head of the Labour Party, attacking him for ruling out supporting Progress's plans to tighten immigration policy in a speech on May 1.
"For eight years, the Labour government sat and talked about action. Jonas Gahr Støre even chaired a committee that came up with several good suggestions," she said. "But now he shows his true self. He would not do anything then, and he will not do anything now."
She argued that Labour's inaction on immigration had left the country with an inadequate system.
"The legacy is both a bad immigration policy and a lousy integration policy," she said. "That's why we should be happy that we have two capable ministers from Progress governing this now: Anders Anundsen and Solveig Horne."
Jensen deftly countered critics who point out the contrast between Progress's radical, populist statements outside government and the much more measured, technocratic approach of its ministers.
"Although we have done a lot already, we also had to take some losses," she said. "I know you are impatient , so am I. . I'm very proud but very hungry. It is in Progress's soul, and that is our strength. But sometimes I try to pause a little, and enjoy the fact that we have implemented some things Progress has wanted to achieve for 41 years."
The Progress Party's annual conference weekend, which began on Friday, did display some of the party's recent power struggles.
Christian Tybring-Gjedde, one of the party's most outspoken anti-Islam and anti-immigration figures, was absent from the conference after falling out with the party leadership.
Louis Edvardsen, who this week described the party's deputy leader Per Sandberg as "a pus boil", or cancer, within the party, was also nowhere to be seen.