At one stage, he was a partner of John Hinderaker at Faegre and Benson. He is now Senior Vice President of the TCF National Bank in Minneapolis.
Johnson started working with Hinderaker on opinion pieces on tax, welfare reform and other public policy issues. The articles were run in conservative publications such as National Review and a wide range of newspapers. Both Johnson and Hinderaker became involved with the Claremont Institute along with Paul Mirengoff, who was Hinderaker's roommate at Dartmouth.
Hinderaker, Johnson and Mirengoff founded the Power Line Blog in 2002. It quickly became a popular site for conservatives as blogging became more important in politics. On September 9, 2004 Johnson posted the "61st Minute" on flaws in the Killian documents used on a 60 Minutes Wednesday story on the George W. Bush military service controversy.
The story quickly spread to other blogs and then to the mainstream media. After defending the veracity of the documents for two weeks, CBS reversed its position and admitted that the documents had not been properly authenticated. After an internal investigation, producer Mary Mapes was fired by CBS, several other executives resigned and CBS apologised to viewers. In 2005, Mapes published a book Truth and Duty claiming that Karl Rove was the mastermind behind the attacks. The CBS public eye stated in a review "there's no evidence brought forth - just assertion."
As a result of the 61st Minute Power Line became even more popular obtaining half a million hits on US Election Day in November 2004. The site was named as the first Time Blog of the Year with Lev Grossman writing in the article "Before this year, blogs were a curiosity, a cult phenomenon, a faintly embarrassing hobby on the order of ham radio and stamp collecting. But in 2004 blogs unexpectedly vaulted into the pantheon of major media, alongside TV, radio and, yes, magazines, and it was Power Line, more than any other blog, that got them there." As a result of the increased profile, Johnson was asked to appear on television political shows on networks such as CNN.
Reproduced in Biography Resource Center. Farmington Hills, Mich.: Thomson Gale. 2005. http://galenet.galegroup.com/servlet/BioRC