It is often claimed by descendants that Walter White is descended from US President William Henry Harrison through an affair with one of his slaves resulting in six children. Although his grandmother was named Marie Harrison, this relationship has not been proven. It has also been surmised that Walter was 1/64th black, but that cannot be ascertained at this time.
Walter Francis White was and American civil rights activist.  He was also an investigator, journalist, novelist, and essayist.  White helped during the launch of the Harlem Renaissance of the 1920s and 1930s.  His books, "The Fire in the Flint," which was tranlated into four languages, and "Flight," a semi-autobiographical novel about an African American who was passing as white, were much read.  He also helped find publishers for Countee Cullen, Langston Hughes, Claude McKay, and Nella Larsen.  White also assisted the careers of Roland Hayes and Marian Anderson.  In keeping with his reputation as a name dropper, he took credit for convincing a young Paul Robeson to leave his career as an attorney and become an actor and concert singer. 
He began his career as an assistant to the Executive Secretary of the National Association for the Advancement of Colored People (NAACP).  He often traveled to gather information and to investigate over 40 lynchings and riots.  His appearance aided him in this endeavor because although he was of mixed race, he appeared to be Caucasian. His biographer, Kenneth Janken, called him a "voluntary Negro" because he could pass himself off as white when he needed to, but chose to recognize the fact that he was in fact not white.  In 1917 on his World War I Draft Card, he was described as short in stature, of slender build, blue-eyed with golden hair.  Conversely, in his 1921 passport application, he was described as tall with a high forehead, blue eyes, medium nose, moustached, medium chin, brown hair, dark complexion (fair crossed out), narrow face.  By 1942 he is described as 5' 7 1/2" tall, negro, blue eyes, gray hair, light complexion, appendix scar. 
He succeeded [[Johnson-51685|James Weldon Johnson] as Executive Secretary of the NAACP, a position he held for twenty-five years.  During his leadership the membership of the NAACP quintupled.  White oversaw the organization's fight against segregation.  He also worked with President Truman on desegregating the armed forces after WWII and gave him a draft for the Executive Order to implement this change.  Under his leadership, the Legal Defense Fund was set up.  This fund was instrumental to numerous legal challenges to segregation and other disfranchisement.  They did achieve many successes to include the Supreme Court determination in Brown v. Board of Education (1954), which ruled that segregated education was inherently unequal. 
Walter Francis White was born 1 July 1893 in Atlanta, Georgia.  His parents were George W. White and Madeline Harrison. 
Walter died 21 March 1955 in New York City. The "Chicago Defender" one of the most influential black weeklies eulogized White thusly, "Fifty years from today, when the rivers flowing and the democracies have eddied into every area barren of democracy, men the world over will still be acknowledging Walter White as a poet of freedom and author of justice."  Although President Dwight D. Eisenhower issued a statement honoring White and Vice President Richard Nixon announced to the press that he had lost a "very dear and good friend," not long after his death, White seems to have been forgotten as not much of anything was written about him. 
Walter White married Leah Gladys Powell, the daughter of William I. and Harriet Josephine (Miller) Powell. They were married in Tompkins, New York on 16 February 1922.  Their marriage lasted 27 years before it ended in divorce.  He secondly married Polly Cannon (1905-1975), a white woman from South Africa.  At the time, this union was considered scandalous and his ex-wife and children cut ties with him (most likely because he is rumored to have had an affair with Polly precipitating the divorce). 
Wikipedia contributors. "Walter Francis White." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 11 Jan. 2018. Web. 17 Jan. 2018.
Marriage Records. New York Marriages. Various New York County Clerk offices. Ancestry.com. New York, County Marriage Records, 1847-1849, 1907-1936 [database on-line]. Lehi, UT, USA: Ancestry.com Operations, Inc., 2016. Film Number: 001008785.
"United States World War I Draft Registration Cards, 1917-1918," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:KZZ3-XM2 : 12 December 2014), Walter F White, 1917-1918; citing Atlanta City no 4, Georgia, United States, NARA microfilm publication M1509 (Washington D.C.: National Archives and Records Administration, n.d.); FHL microfilm 1,556,952.
United States, Selective Service System. Selective Service Registration Cards, World War II: Fourth Registration. Records of the Selective Service System, Record Group Number 147. National Archives and Records Administration. Ancestry.com. U.S., World War II Draft Registration Cards, 1942 [database on-line]. Lehi, UT, USA: Ancestry.com Operations, Inc., 2010. The National Archives at St. Louis; St. Louis, Missouri; Record Group Title: Records of the Selective Service System, 1926-1975; Record Group Number: 147, Serial Number: U1267.
"United States Passport Applications, 1795-1925," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:QV5Y-Y98C : 4 September 2015), Walter Francis White, 1921; citing Passport Application, New York, United States, source certificate #68310, Passport Applications, January 2, 1906 - March 31, 1925, 1698, NARA microfilm publications M1490 and M1372 (Washington D.C.: National Archives and Records Administration, n.d.) Certificate Number: 68310.
"New York, New York Passenger and Crew Lists, 1909, 1925-1957," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:242D-P31 : 2 October 2015), Walter White, 1938; citing Immigration, New York, New York, United States, NARA microfilm publication T715 (Washington, D.C.: National Archives and Records Administration, n.d.).
United States of America, Bureau of the Census, Twelfth Census of the United States, 1900, Washington, D.C.: National Archives and Records Administration, 1900. T623, 1854 rolls. (Ancestry.com. 1900 United States Federal Census [database on-line]. Provo, Utah: Ancestry.com Operations Inc, 2004). Year: 1900; Census Place: Atlanta Ward 6, Fulton, Georgia; Page: 11; Enumeration District: 0078.
George W. White, Feb 1857, mail carrier
Madaline White, Feb 1864
George M. White, Jul 1883
Alice White , May 1887
Ollie M. White, Nov 1889
Walter F. White, Jul 1892
Ruby White, Jan 1897
Helen White, Mar 1899
Thirteenth Census of the United States, 1910 (NARA microfilm publication T624, 1,178 rolls). Records of the Bureau of the Census, Record Group 29. National Archives, Washington, D.C. (Ancestry.com. 1910 United States Federal Census [database on-line]. Provo, Utah: Ancestry.com Operations Inc., 2006). Year: 1910; Census Place: Atlanta Ward 6, Fulton, Georgia; Roll: T624_192; Page: 10A; Enumeration District: 0085; FHL microfilm: 1374205.
George W White 54
Madeline White 44
George N White
Ollie M White 20
Walter F White 16
Ruby H White 13
Helen E White 11
Madeline White 9
Fourteenth Census of the United States, 1920., (NARA microfilm publication T625, 2076 rolls). Records of the Bureau of the Census, Record Group 29. National Archives, Washington, D.C. For details on the contents of the film numbers, visit the following NARA web page: NARA. Note: Enumeration Districts 819-839 are on roll 323 (Chicago City). Ancestry.com. (1920 United States Federal Census [database on-line]. Provo, Utah: Ancestry.com Operations, Inc., 2010. Images reproduced by FamilySearch). Year: 1920; Census Place: Manhattan Assembly District 21, New York, New York; Roll: T625_1224; Page: 4A; Enumeration District: 1436.
Walter White, 26, lodger, hotel porter
United States of America, Bureau of the Census. Fifteenth Census of the United States, 1930. Washington, D.C.: National Archives and Records Administration, 1930. T626, 2,667 rolls. Ancestry.com. (1930 United States Federal Census [database on-line]. Provo, Utah: Ancestry.com Operations Inc, 2002). Year: 1930; Census Place: Manhattan, New York, New York; Roll: 1578; Page: 1A; Enumeration District: 1053; FHL microfilm: 2341313.
Walter White 35
Gladys White 36
Jane White 7
Walter White 2
United States of America, Bureau of the Census, Sixteenth Census of the United States, 1940, Washington, D.C.: National Archives and Records Administration, 1940. T627, 4,643 rolls. Ancestry.com. (1940 United States Federal Census [database on-line]. Provo, Utah: Ancestry.com Operations, Inc., 2012). Year: 1940; Census Place: New York, New York, New York; Roll: m-t0627-02667; Page: 2B; Enumeration District: 31-1803.