The legislation, which was approved by a vote of 49-36 out of the Knesset's 120 lawmakers, replaces a 2014 law that would have ended the exemption by 2017.
The law, which enables a further three-year "adjustment period" beyond the six, is a victory to the ultra-Orthodox parties in Prime Minister Benjamin Netanyahu's coalition.
The 2014 legislation stipulating military or civilian service to ultra-Orthodox men was passed at the insistence of then finance minister Yair Lapid, whose Yesh Atid party was a central component of Netanyahu's government at the time.
The 2014 law was seen by many Israelis as amending the historic injustice of an exemption handed to the ultra- Orthodox in 1948, when Israel was created.
At that time they were a small segment of society.
The ultra-Orthodox have since swelled to make up roughly 10 per cent of Israel's population of just over eight million, and continues to be the country's fastest-growing community.
They believe their study of Jewish scripts serves Israel no less than military service, and leaders of some of the closed ultra-Orthodox communities fear the effects of integration into general Israeli society via joint military service.
Hanegbi said the new law was a means of advancing the principal of conscription based on "changing the dialogue and cooperating with the ultra-Orthodox."
Lapid filed a petition to the high court against the legislation yesterday.
