Aso, 68, president of the Liberal Democratic Party and a former Japanese foreign minister, won enough votes in the Diet to gain the premiership. At his first news conference, Aso unveiled a Cabinet that included both close allies and former rivals, the Kyodo news agency reported.
Aso said he would concentrate on the faltering Japanese economy and named fellow LDP stalwart and conservative Shoichi Nakagawa, 55, as finance minister and financial services minister, while Takeo Kawamura, 65, assumed the post of chief Cabinet secretary.
Former Education Minister Hirofumi Nakasone, 62, was named as foreign minister, while Yasukazu Hamada, 52, became defense minister, Kyodo reported.
Analysts said Aso mixed friends and former enemies in his Cabinet in order to build unity heading into a general election, which is expected to be called soon.