Effie Achtsioglou, a 31-year-old Labour Ministry official who participated in the negotiations with the foreign lenders, was appointed labour minister.
"The prime minister tidied up his cabinet," head of Alco polling agency Costas Panagopoulos said.
"This scheme seems more capable to fulfill the country's international obligations."
Tsipras set up stand-alone ministries to handle tourism - the economy's key driver - and the crucial issue of migration, as Europe struggles with its worst migrant crisis in decades and thousands are stranded in the cash-strapped country.
Migration Minister Yannis Mouzalas kept his post, along with the ministers of foreign affairs, defense and tourism. Greece is expected to return to growth in 2017, an event which Tsipras hopes will convince Greeks that their sacrifices are paying off.
Tsipras' closest aide and adviser Nikos Pappas - who as state minister oversaw an auction on television licenses that was annulled by a top court, was appointed minister of digital governance and media.
Tsipras was first elected in January 2015 promising to end years of austerity, but he reversed course six months later and signed up to a new bailout, Greece's third aid program since the country's debt crisis broke out in 2010.
He was re-elected in September last year, but his popularity ratings have been dropping for months and his Syriza party has been trailing the conservative New Democracy party.
Follow CNBC International on Twitter and Facebook.