"If I were to choose the 50 best in 50 years, I wouldn't be one of them," Mendez said. "This is an honor. When I found out about it, I was blown away. It's hard to comprehend that it's happening."
The CIA said that Mendez' ideas "led to the design and deployment of a series of increasingly sophisticated tools that enabled operations officers to change their appearance convincingly.
"His vision and artistic skill had a major impact on the agency's operational capabilities in hostile environments."
Mendez, 56, said he worked for years helping disguise and create false documents and identities for espionage agents funneling information to the United States.
The job of "espionage artist" for the agency was only one of several he held within the CIA, Mendez said.
By the time he retired from the agency six years ago, Mendez said he had risen to a rank within the CIA "equivalent to a two-star general."
The Trailblazer award won't be the first for Mendez, who in 1980 received the Intelligence Star medal from the CIA for his "courageous and heroic performance during an unprecedented intelligence undertaking" in a foreign country.
According to the CIA, Trailblazer nominations "were limited to individuals who at any point in the CIA's history distinguished themselves as leaders, made a real difference in CIA's pursuit of its mission and who served as a standard of excellence for others to follow."
Accomplishments of those chosen for the Trailblazer award range from weapons intelligence analysis to the laying of groundwork for clandestine operations, the CIA said.
Thursday's ceremonies will cap several days of events commemorating the CIA's half-century of service.
Mendez said he retired from the CIA at age 50 to devote full time to his "second career" as an artist. He lives with his family on 40 acres in Pleasant Valley.