But his marriage to the president's daughter, Dinara, might be as important as his employment history.
Kazakhstan has huge, relatively untapped oil and gas fields. The country's export potential is limited due to a lack of export routes, but it has joined up recently with several major pipeline projects to feed energy-hungry countries both East and West.
Bolatkhan Taizhan is a political analyst and a former Kazakh ambassador to Malaysia, a country that has invested heavily in Kazakhstan's oil sector. He says President Nazarbaev stands to gain the most from Kulibaev's appointment.
"This means that [President] Nazarbaev's family is gaining power," Taizhan says. "Nazarbaev seems to have managed to get the major sector of the national economy directly into his own hands through the appointment of his son-in-law to that position. Of course, even before [Kulibaev's appointment], all the sectors were under President Nazarbaev's control. But now -- and I have to repeat this -- the appointment of his son-in-law to that position means direct control of the sector for Nazarbaev."
Oraz Zhandosov is a former Kazakh trade, industry, and economy minister who is now a senior member of the opposition Naghyz Ak Zhol party. He claims Kulibaev's appointment is a continuation of presidential politics at the expense of sound government.
"It happened long ago and it continues," Zhandosov says. "[Kulibaev's appointment] is a conflict of interest."
President Nazarbaev's office has not commented on the appointment.
Several of Nazarbaev's children and their spouses have prominent positions in Kazakhstan's heavily intertwined public and private sectors. Kulibaev and his wife, Dinara, indirectly control a majority stake in the country's third-biggest bank, Halyk Bank. President Nazarbaev's eldest daughter, Darigha, is the head the pro-presidential Asar, a member of parliament, and wields much influence in the state media sector. Darigha's husband, Rakhat Aliev, is a deputy foreign minister.
Dos Koshim, the chairman of the nongovernmental Network of Independent Observers, says Kulibaev's appointment might have something to do with a possible family rift. Koshim suggests the move is aimed at countering presidential daughter Darigha and her husband's growing influence in Kazakhstan -- and their perceived independence from Nazarbaev himself.
"For me, the recent changes with the positions of this sector seem like a campaign by Nazarbaev to accrue more power in his own hands," Koshim says. "[Long-time presidential supporter] Kairat Kelimbetov's appointment to the Stable Development Fund Qazyna, [and] the appointment of [Nazarbaev's] second son-in-law, Kulibaev, as director KazMunaiGaz -- all this looks like Nazarbaev's attempt to base his powers not on Darigha and Rakhat, but on his second son-in-law. And it looks to me like a clear message."
Koshim also points to a recent appointment of Ermukhammet Ertisbaev to head the Information Ministry as further evidence that Nazarbaev is stacking the deck. Ertisbaev is a former adviser who has been Nazarbaev's point man this year in fielding criticism from eldest presidential daughter Darigha over a range of issues.
But whatever the implications within the family, second son-in-law Timur Kulibaev is now in charge of one of Kazakhstan's biggest sources of revenues.
(Merhat Sharipzhan of RFE/RL's Kazakh Service contributed to this report.)