The unnamed SEAL --a member of SEAL Team Six, the group that took down Osama Bin Laden-- fell in an assault on Dilip Joseph's captors.
"He gave his life for his fellow Americans, and he and his teammates remind us once more of the selfless service that allows our nation to stay strong, safe and free," President Barack Obama said.
Joseph and two other Afghan health workers from Morning Star Development -- a nonprofit that provides medical care in rural areas -- were kidnapped on Wednesday. The two Afghanistans were released Saturday following negotiations. According to CNN, the family of one of the Afghani men relinquished $12,000 for his release.
At the time of his fellow doctors' release, Joseph was believed by International Security Assistance Force to be in imminent danger of injury of death.
Gen. John Allen authorized the mission Saturday night that rescued Joseph in the Laghman province, a mountainous region near Pakistan.
"Today's mission exemplifies our unwavering commitment to defeating the Taliban," Allen said in a statement. "I'm proud of the American and Afghan forces that planned, rehearsed and successfully conducted this operation. Thanks to them, Dr. Joseph will soon be rejoining his family and loved ones."
Joseph, according to Morning Star, has worked for the agency for three years, serving as a medical adviser and traveling frequently to Afghanistan.
His family expressed their "deepest condolences to the family of the American sailor who died during Dilip's rescue."
"We are incredibly grateful for the multiple agencies of the U.S. government that have supported us in this difficult time, and especially the quick response by our military and partner allies to rescue Dilip," the family added.