Tanaka died of natural causes May 21 at the Ronald Reagan UCLA Medical Center, according to his daughter, Christine.
As editor of the English-language section of the bilingual newspaper Rafu Shimpo, Tanaka helped oversee the last issue in the spring of 1942 before 110,000 Japanese Americans on the West Coast were rounded up under President Franklin D. Roosevelt's Executive Order 9066 and forced to relocate to detention centers scattered across several states. Tanaka was sent to Manzanar, in the Owens Valley at the foot of the Sierra Nevada.
Because of his journalism background, Tanaka worked as a camp historian documenting the internee experience for the War Relocation Authority. He also wrote reports for a UC Berkeley study on the evacuation and resettlement of Japanese Americans during the war.
"He left hundreds of rich daily accounts of everyday life" at Manzanar, said USC professor Lon Kurashige, an expert on Japanese American history and identity. "These reports . . . are a rare and intelligent window into not just Manzanar but Japanese American life in pre-war Los Angeles."
His diligent reporting on every aspect of camp life, including the political factions dividing Manzanar's population, "got him into a lot of trouble," said Arthur Hansen, a Manzanar scholar and emeritus professor of history and Asian American studies at Cal State Fullerton.
So did Tanaka's unflinching support of the United States. He advocated cooperation with the government that had branded lawful Japanese Americans as security threats and forced them to give up their homes and livelihoods for confinement behind barbed wire.
"What we didn't realize at the time was that we would soon be identified as informers, spies and dogs, people who were abusing or invading the privacy of the evacuees," Tanaka said decades later of himself and another camp historian. Stripped of his liberty by the U.S. government and hated by many of his fellow Japanese Americans, he was "truly in a no man's land," said his son, Wesley.
Born in Portland, Ore., on Jan. 7, 1916, Tanaka grew up in Los Angeles, where his immigrant parents ran a small vegetable store. At 16, he graduated from Hollywood High School and entered UCLA, where he wrote for the Daily Bruin and majored in political science, earning a bachelor's degree in 1936.
In his senior year he was hired by the Rafu Shimpo, the leading Japanese American daily in Southern California, to edit its English-language section. He wrote editorials urging Nisei -- the first generation of American-born Japanese -- to be loyal and patriotic citizens.
"He was a mentor for a lot of us Nisei who were aspiring to be in the journalism game," said veteran journalist Harry Honda, who worked under Tanaka in the 1930s.
As U.S. relations with Japan deteriorated, Rafu Shimpo's publisher sent Tanaka to Washington to seek assurances that the newspaper would be allowed to continue publishing when war came. His request landed him in an interrogation room of the War Department, where officers insinuated that his patriotism was a sham.
The day after Pearl Harbor was bombed Dec. 7, 1941, FBI agents arrested scores of Japanese immigrants considered "enemy aliens." Tanaka was one of the few American-born Japanese rounded up in the sweep. He was held for 11 days without explanation and was not permitted to contact anyone, including his wife, Jean, who was expecting their first child.
He was released on the 12th day without having been charged with any crime. Four months later, on April 23, 1942, he and his family were evacuated to Manzanar, which would eventually be occupied by 10,000 people of Japanese descent, most of whom were U.S. citizens from Los Angeles County. He described Manzanar as an "outdoor jail," where internees lived in rough-hewn barracks filled with dust blown in by windstorms and got sick from eating ill-prepared food.
Many of the reports he filed at Manzanar were critical of camp administrators and the policy that led to internment. "I cannot see how it is possible for any human being of normal impulses to be cooped up within limited confines of barbed wires, watchtowers, and all the atmosphere of internment and not be touched by the bitterness and disillusionment all around him," he wrote.
On the eve of the first anniversary of the Pearl Harbor attack, unrest swept Manzanar. The targets were people like Tanaka who favored cooperation with camp authorities and the U.S. government. Led by pro-Japan internees, an angry mob stormed Tanaka's barracks but found only his wife and infant daughter. Warned of their approach, Tanaka had disguised himself and hid in the crowd, with a knife under his coat to defend himself and his family.
Two protesters died as a result of the rioting, but Tanaka and his family were saved. Camp officials removed him and a few dozen others who had been branded as collaborators to another camp in Death Valley. In 1943 he moved to Chicago and spent the remainder of the war years as a volunteer for the Quakers, helping to find jobs and housing for refugees from the Nazi concentration camps and Japanese Americans released from internment.
Having suffered numerous traumas because of his former profession, Tanaka did not return to journalism after the war. He headed the editorial department of a Chicago textbook publisher and helped start a company that published Scene magazine, which covered Asian affairs.
In 1955 he moved back to California and started a company that produced trade publications. In 1963 he founded Gramercy Enterprises, a highly successful real estate holding company. He retired as board chairman in 1985.
In 2005, he returned to Manzanar, where he found his desk and typewriter preserved in a permanent exhibit. "We were very touched to see him," said interpretive park ranger Richard Potashin, who had helped plan the exhibit. "It was like history walking in the front door."
Tanaka is survived by his wife of 68 years, Jean Miho Tanaka of Westwood; three children; five grandchildren; and eight great-grandchildren. A memorial service will be held July 17. For more information, call (310) 598-7912.