Ahmed Abdel Qader, 33, a prominent campaigner and founder of the Eye on the Homeland newspaper, was attacked by two gunmen during a drive-by shooting in Sanilurfa on Sunday afternoon.
The newspaper reported the incident on its Facebook page, confirming Mr Qader had been shot three times during the assassination attempt.
Isis immediately claimed the attack in a statement through its propaganda channels.
Qader survived the shooting and remained in hospital in a stable condition, according to ABC News.
Qader also founded the campaign group “Raqqa is Being Slaughtered Silently” (RBSS), which has been awarded for its on-the-ground reporting of the conflict.
The newspaper and its sister radio station have repeatedly expressed strong opposition to the actions of Isis on the Syria-Turkey border in print and broadcasts.
He claimed in an interview with AP after his brother’s death that he had been “receiving threats” from Isis regularly for a while.
One of Qader’s colleagues, who requested anonymity, said the gunmen had used silencers and escape quickly on a motorbike.
The shooting follows the death of two other Syrian journalists at the hands of Isis over the past six months.
Online broadcaster Mohammed Zahir al-Sherqat was shot in the neck in April and anti-IS filmmaker Naji Jerf was gunned down in Gaziantep in December.
Several members of RBSS have been killed by Isis members in Raqqa. In May 2014 Al-Moutaz Bellah Ibrahim was kidnapped by the group and later murdered.
In July 2015, Isis released a video showing two men from the organisation being strung up on trees and shot.
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