Pak Pong-ju started out his career by managing a food factory near the border with China. In 1962, he was appointed the manager of the Yongchon food factory in North Pyong'an Province.
By the 1970, he became an industrial manager and also became involved with the ruling Korean Workers' Party (KWP) as a party cadre. He then served as a party manager of the DPRK’s chemical industries and was elected as an Alternate Member of the WPK Central Committee during the 6th Party Congress in October 1980.
He was appointed the party secretary of the Namhu’ng Youth Chemical Complex in July 1983 and became the Chief Secretary of the facility in 1989. In the meantime, he went on to visit former Czechoslovakia, Poland and Hungary in May 1987.
In the early 1990s, he shifted from the chemical industry to the light industry and became Kim Jong-il's sister Kim Kyong Hui’s principal deputy at the CC KWP Light Industry Department in 1993. He became the vice director of the party's Economic Policy Supervisory Department in March 1994.
At the time of the death of North Korean leader Kim Il-sung, he managed to make into the funeral committee with a rank of 188 among 273 members in the elite hierarchy. However, by July 1998, he was elected deputy to the 10th Supreme People’s Assembly, following which he returned to the chemical industry after being appointed Minister of Chemical Industry by the then-premier Hong Song-nam.
Five years later, in August 2003, he was appointed deputy to the 11th Supreme People’s Assembly. The following month, he replaced Hong Song-nam as the new DPRK Premier.
In October 2005, he was a member of the Yon Hyong Muk Funeral Committee and the same year, during a plenary session of the Supreme People's Assembly, he proposed an administrative solution to food distribution. He also proposed to reintroduce the July 2002 economic reforms, labeling it to be the official stance of the party.
During his first tenure as Premier, he made two trips to China with Kim Jong-il in April 2004 and October 2006, and another time in March 2005 as the head of a high-level delegation. However, he made no public appearances since May 2006 and, was "relieved … of premiership" during the 5th session of the 11th Supreme People's Assembly in April 2007, reportedly because of his China-focused economic developments.
Kim Yong-il, a former Minister of Land and Marine Transport, replaced him as the new premier, following which his whereabouts remained unknown till he appeared on DPRK television in 2008. At the time, he was identified as a factory manager, and according to current sources, joined as the manager of Sunch’o’n Vinalon Factory in May 2007.
He is thought to have returned to the power center in 2009 and became the deputy director of WPK Light Industry Department in March that year. Based on information from state-run Korean Central Television, 'New York Times' reported on August 23, 2010, that he had been reinstated as the first deputy director of the Central Committee of the ruling party.
In September 2010, he was elected as a member of the 6th Congress Committee of the Workers' Party of Korea. Pong-ju, who had served as the deputy director of the Party Light Industry Department in 1993-98, regained that position in 2010-2012, and replaced Kim Jong-il's sister Kim Kyong-hui as the director in April 2012.
Thanks to the work he did for Kim Kyong-hui, he was close to her husband Jang Sung-taek, who rose in the power hierarchy during the shifting of the government's attention to the consumer economy. He was elected to Politburo Standing Committee on March 31, 2013, and replaced Choe Yong-rim to become the Premier for a second term on the following day.
He addressed the first full session of the cabinet on April 22 and discussed the 'Byungjin Line', which advocated pursuing the parallel goals of economic development and a robust nuclear weapons program. It was announced by July 2013 that his cabinet had taken full authority over economic measures by calling to "unconditionally executing the cabinet’s decisions and instructions".
Pak Pong-ju has been credited for leading a process of quiet reform inside North Korea that helped DPRK's economy survive sanctions since 2002, as well as for reintroducing the July 2002 economic reforms later. While he was sacked a few years into his first tenure as the premier, his reinstatement in 2013 signaled to the world the return of pragmatists and reformists into power.
Touted as the market-oriented reformer by the international media, he is thought to be one of the greatest hopes for people in North Korea, who want to live a happier and more fulfilling life. He is also considered an able and charismatic leader as he has survived being purged in the late 2000s and is now one of three most powerful people in the country.