JAKARTA, Indonesia — The campaign for governor of Indonesia’s chaotic capital has, at times, resembled a rock concert, punctuated by guitar riffs, fist pumps and checkered shirts. At its heart is Joko Widodo, a candidate whose message of change has propelled him into the upstart contender for leader of one of Asia’s most important metropolises.

In July, Mr. Joko, the mayor of Surakarta in Central Java, surprised pollsters by emerging from the first round of elections with 43 percent of the vote, ahead of the man who had been expected to win, Gov. Fauzi Bowo, who took 34 percent. With none of the six candidates winning a majority, Mr. Joko and Mr. Fauzi will compete in a runoff on Thursday.

This is only the second time Jakarta residents have voted for their city’s leader directly, and Mr. Joko, with his signature checkered shirts and populist manner, has injected new enthusiasm into the process. In a country where politicians often come from a tight-knit elite or have ties to the late president and military strongman Suharto, Mr. Joko, best known by his nickname Jokowi, appears to represent a new breed of politician, analysts say.

A furniture exporter who entered politics for the first time when he ran for mayor in 2005, he is widely perceived as clean and capable in a country beset by corruption — Transparency International ranked Indonesia 100th out of 182 countries in 2011. As mayor of Surakarta, Mr. Joko helped relocate street vendors to ease traffic congestion and introduced a modern tram system. He streamlined business application procedures, widened access to health services and cleaned up slums, the last an issue with special appeal to Jakarta voters. In 2010, he was re-elected with 90.9 percent of the vote. He is on the short list for World Mayor 2012, an award given out every two years by the City Mayors Foundation, an international research organization.