"Sergeant Major (reservist) Yehezkel Azaria, from Petah Tikva... fell during an operational activity in the Margaliot area, aged 53 at the time of his death," the army said in a statement.
A military spokesperson confirmed to AFP that two soldiers were also wounded in the attack, which was the result of an incursion by an unspecified "hostile aircraft".
The army had reported the incursion earlier in the day, saying that air defences "intercepted a hostile aircraft that crossed from Lebanon into Israel".
"An additional hostile aircraft that crossed from Lebanon was identified and fell in Margaliot... In response, IDF artillery is striking in Lebanon," it added.
Azaria is the seventh Israeli soldier to be killed on Lebanese border since the outbreak of the Israel-Hamas war in the Gaza Strip.
Since October 8, the day after the war started, the frontier has seen deadly exchanges of fire, mainly between the Israeli army and the Iran-backed Hezbollah movement, which says it is acting in support of Hamas.
On Friday, residents said the Israeli army dropped leaflets on parts of southern Lebanon for the first time since hostilities flared, warning them not to help Hezbollah.
Since the cross-border exchanges began, more than 120 people have been killed on the Lebanese side, most of them Hezbollah fighters but also a Lebanese soldier and 17 civilians, three of them journalists, according to an AFP tally.
On the Israeli side, four civilians have been killed in addition to the seven soldiers, authorities have said.
