Subhi Abu Khalifa confessing to stabbing and seriously wounding an ultra-Orthodox Jewish student and lightly injuring a guard in northern Jerusalem, according to the ruling published by the court.
Khalifa, 19 at the time and originally from the Shuafat refugee camp in annexed east Jerusalem, in May accepted an 18-year plea bargain agreed between the prosecution and the defence.
Jerusalem district court ratified the agreement on Monday.
Another Palestinian youth accepted an 18-year plea deal for manslaughter, the court said.
Abed Dawiat, 20, was accused of throwing stones at a car in September 2015 in east Jerusalem, causing the death of Israeli driver Alexander Levlovich.
The plea bargain still needs to be approved at hearings scheduled for December.
A justice ministry spokesman told AFP the courts generally approve sentences agreed between the prosecution and the defence.
Israel occupied Palestinian east Jerusalem in 1967 and later annexed it.
The two attacks took place at the beginning of a wave of violence that began in October 2015.
Since then, violence in Israel and the occupied Palestinian territories has claimed the lives of 239 Palestinians, 36 Israelis, two Americans, a Jordanian, an Eritrean and a Sudanese, according to an AFP count.
The situation has calmed down significantly in recent months.
Most of the Palestinians killed were carrying out attacks, according to Israeli authorities. Others were shot dead during protests and clashes, while some died in Israeli air strikes in Gaza.
Earlier this month, an Israeli court sentenced three Palestinian minors convicted of stabbings to more than 10 years each in prison.
