Sadyr Japarov, 51, was this week freed by his supporters from prison where he was serving a lengthy sentence on charges of taking a state official hostage in a 2013 incident.
Kyrgyzstan's parliament has named Sadyr Japarov prime minister, ending a power vacuum in the Central Asian nation which has been gripped by unrest since October 6.
Japarov, backed by the nationalist AtaZhurt party, told the parliament on Saturday that he would keep the cabinet line-up unchanged.
The 51-year-old was this week freed by his supporters from prison where he was serving a lengthy sentence on charges of taking a state official hostage in a 2013 incident.
Earlier in a session, speaker Myktybek Abdyldayev said he would resign after less than a week in the post. Abdyldayev said the session had a quorum.
Reshuffling of officials
Meanwhile, Kyrgyz President Sooronbay Jeenbekov sacked security council secretary Damir Sagynbayev and his deputy Omurbek Suvanaliyev, the president's office said, after declaring a state of emergency amid unrest.
Jeenbekov named Zhanybek Kaparov new deputy secretary of the council which coordinates the work of all security forces.
The firing comes shortly after Kyrgyz security forces detained former president Almazbek Atambayev, Russia's Interfax news agency reported citing a member of Atambayev's political party.
Atambayev's supporters had secured his release from prison where he was serving a lengthy sentence on corruption charges amid unrest which toppled the country's government on Tuesday.
Atambayev survived an assassination attempt in Bishkek on Friday when his car was shot at, Russia's RIA news agency cited an aide as saying.
Military in Bishkek
The former Soviet republic of 6.5 million hosts a Russian military airbase and serves as a hub for trade with neighbouring China. It is also home to a large Canadian-owned mining operation.
Military checkpoints were put up overnight around capital Bishkek and armoured personnel carriers were spotted in the city after Jeenbekov ordered troops to deploy and re-establish order amid flare-ups of violence.
The parliament planned to gather in the presidential residence on the outskirts of Bishkek after its own offices were ransacked by protesters who seized key government buildings on Tuesday.
'Chaos' in the country
Russia, which exerts significant influence on Kyrgyzstan, this week described the situation as "chaos".
More than 1,200 people have been injured and one person has been killed in street clashes since protests erupted on Monday.
Japarov's supporters clashed with followers of a few other parties on Friday which nominated their own candidate, Omurbek Babanov.
Several people were wounded including a politician nominated to serve as Babanov's deputy.
The opposition is divided between 11 parties which represent clan interests in a country that has already seen two presidents toppled by popular revolts since 2005.
READ MORE: Why are people in Kyrgyzstan protesting?