[1] Johanson graduated from Moanalua High School in Salt Lake on the island of Oahu and then from Yale University, where he received a BA in history.

[4] When Republican State Representative Lynn Finnegan of the 31st District retired to run for Lieutenant Governor of Hawaii in the 2010 election, Johanson ran to succeed her.

[9] Widely regarded to be a "rising star" in the Hawaii Republican Party, at just 32 years of age, he was the youngest person to hold the post in recent history.

State Representative Cynthia Thielen, the longest-serving Republican House member, cried when lamenting his move, blaming right-wing conservatives for pushing him out and saying that the Party had lost a "wonderful, moderate voice.

"[10] By contrast, Party Chairwoman Pat Saiki called his move "disgraceful" because he had been re-elected as a Republican less than two months prior, saying that it was "disappointing" that he was "willing to sacrifice his own political principals for his own ambition.

[12] Johanson announced at the end of the 2022 legislative session on May 5, 2022 that he will not run for re-election, and will leave public office to spend more time with his elderly parents.