The 39-year-old is running for one of 113 seats up for grabs in Taiwan's parliamentary elections Saturday the same day the island picks a new president.
As he does with his music, he hopes to give voice to the island's young people, many of whom fear a future under the influence of China.
"The government thinks that relying on China will result in economic prosperity, which the youth do not agree with," he told CNN over Skype from his campaign center in Taipei.
For his campaign photos, he's suited up and pinned his long hair back so it's barely visible but Lim, and his newly formed party, has unsettled many in Taiwan's political establishment, who desperately need the younger voters he appeals to.
His opponents don't seem to know how to handle his counter-cultural appeal.
Lin Yu-Fang, the ruling party incumbent in the Taipei district Lim is contesting, on Friday called on voters not to elect a candidate "who has hair that is longer than a woman's," according to the Taipei Times newspaper.
Lim represents a new generation that has grown up taking democracy for granted -- the island had its first presidential election in 1996.
Their elders came of age under martial law and one party rule and mock Taiwan's millennials as the "strawberry generation" -- fragile and easily bruised -- but Lim says this couldn't be further from the truth.
His New Power Party emerged from 2014's "Sunflower Movement," when scores of student protesters stormed and occupied Taiwan's Legislature and Cabinet building to object to a trade pact that symbolized Taiwan's deepening relations with mainland China.
Lim, who'd combined his musical career with being director of Amnesty International in Taiwan for four years, supported them.
Lim's party is one of a number of smaller opposition groups that aim to break the two-party stranglehold of the pro-China and ruling Kuomintang (KMT) and the Democratic Progressive Party (DPP), whose candidate is tipped to win.
"If I entered parliament, the most important thing (that I'd like to change) would be the distrust in politics."
The DPP has traditionally leaned in favor of independence but its pragmatic leader Tsai Ing-wen is seen as unlikely to reverse the closer ties with China established by the KMT.
Lim says young people don't want Taiwan to become another Chinese territory and look in fear at Hong Kong, where Beijing is tightening its grip.
"I hope Taiwanese people can appreciate more of the precious freedom, democracy and independence we have today. Even a free society like Hong Kong has become so miserable thanks to the Chinese government's involvement."
A big turnout among younger voters is expected on Saturday and Johnny Yeh says Lim's party has his vote. A student at Tsinghua University in Beijing, he's flying home on Friday to cast a ballot for the very first time.
"I hope that Taiwan can be more independent from the mainland, both economically and politically. Maybe Taiwan can trade more with other countries," he told CNN by phone.
China and Taiwan -- officially the People's Republic of China and the Republic of China -- separated in 1949 following the Communist victory in the civil war.
The two sides have been governed separately since, though a shared cultural and linguistic heritage mostly endures -- with Mandarin spoken as the official language in both places.
Yeh's classmate and compatriot Mark Tsai traveled back to Taiwan Wednesday. He wouldn't reveal who he would vote for but said it was very important for him to take part in the election.
"Many people of my parents' age don't tend to vote, because they don't think it does much for politics or even Taiwan. But for younger people like me, who are voting the first time, many feel idealistic."
It's this enthusiasm that Lim hopes to be able to tap and a key part of his platform is to lower the voting age from 20 to 18.
Music of politics
After two decades of touring the world with "Chthonic" -- pronounced "thonic" and sometimes described as Asia's "Black Sabbath"-- Lim says he's ready for the challenge of political office.
His music and star appeal has raised his profile -- he gave a free concert at a rally on December 26 that reportedly attracted tens of thousands of people
-- although he says he's made his music more "symphonic" for campaign purposes.
His band members are supportive but he says he can't count on resuming his music career if he fails to get elected: "They said they would only be willing to work with me again if I won."