The convictions were a "badge of honour" Mr Nasrallah said
The leader of the Lebanese Shia militia Hezbollah has strongly criticised the Egyptian courts for jailing men accused of working for the group.
Hassan Nasrallah said the judgement by the Security Court in Cairo was "unjust and politicised" in an interview with an Arabic TV station.
He said he would seek "political and diplomatic means" to get their release.
The 26 men were sentenced by the court for planning terrorist attacks on ships and tourist sites.
Hezbollah says it was working to smuggle weapons into the Gaza Strip.
"The verdicts that were issued... against the mujahideen who were providing support for the mujahideen in Gaza are political and unjust... against these honourable mujahideen," he was quoted as saying.
Mr Nasrallah said the convictions were a "badge of honour" for the men.
Muslims should consider it a "source of pride" that members of Hezbollah were jailed helping Palestinians, he told al-Rai TV.
One of the men is Lebanese citizen Sami Shihab, last year Mr Nasrallah confirmed he was a Hezbollah operative.
He was given a life sentence which cannot be appealed against.
The others, 18 Egyptians, five Palestinians, a Sudanese man and another Lebanese man, were given sentences that ranged from six months to 25 years, some with hard labour.
Four of those sentenced are still on the run, including the alleged Lebanese ringleader, and were convicted in absentia.
Prosecutors said Hezbollah had told the men to collect intelligence from villages along the Egypt-Gaza border, tourist sites and the Suez Canal.
The group had received equipment from Hezbollah, and had also been tasked with spreading Shia ideology in the predominantly Sunni country, the Egyptian government said.
At the start of the trial it was reported that at least one of the accused said he had been tortured while in Egyptian custody.
Hezbollah has said the charges are politically motivated and in revenge for the movement's stance on Egypt's support for the Israeli blockade of Gaza.
Hezbollah supports Hamas - the Islamic movement which controls the coastal enclave - and has strongly criticised Egypt for not opening its border with Gaza to relieve the Israeli-imposed blockade on the territory.