Sioufas has been a member of New Democracy's Central Committee since 1997; previously he was a member of the Central Committee from 1979 to 1985 and from 1994 to 1997.[1][2] He was also a member of the party's Executive Committee from 1997 to 2001 and a member of its Political Council from 2001 to March 2004.[1] From April 2000[2] to March 2004, he was Secretary General of the New Democracy Parliamentary Group.[1]
Sioufas married Kaity Anagnostaki and had two sons and a daughter.[2]