The death raised the toll from Thursday's attack to five.
"Our colleague in Al-Manar television Abbas Karnib has died from the serious injuries he suffered in the terrorist blast that targeted Haret Hreik last Thursday," the broadcaster said.
"He underwent surgery... But he remained in critical condition and passed away this morning."
Born in 1961, Karnib joined Al-Manar's technical department in 1991.
According to the channel, he was "an ex-prisoner in the jails of the Zionist enemy," Israel.
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Al-Qaeda affiliate the Islamic State of Iraq and the Levant claimed responsibility for the bombing and threatened further attacks in Lebanon.
The Lebanese army said on Saturday that the bomber was a 20-year-old Lebanese from the Sunni area of Wadi Khaled in the north.
Lebanon has suffered a spate of bombings and clashes related to the war in neighbouring Syria in recent months.