William P. Stewart, a Civil War veteran, was also an early black settler in Snohomish County, Washington. Stewart was born on December 9, 1839, as a free person of color to Walden and Henrietta Stewart in Sangamon County, Illinois. He had five other siblings, four brothers and one sister, and was living in Forest, Wisconsin, in 1860.

When the Civil War broke out in 1861, President Abraham Lincoln resisted the idea of African Americans serving in the military. By 1862, however, he was convinced that in order to militarily weaken the Confederacy, slavery had to be abolished in those states of rebellion (Emancipation Proclamation) and that the recruitment of black men into the Union Army was necessary. When the recruitment drive reached Illinois, William P. Stewart enlisted into the 29th U.S. Colored Infantry Regiment on February 1, 1865, at the age of twenty-five. The almost 56 farmer served for less than a year in the Union Army fighting for the unity of the nation and the freedom for nearly four million enslaved blacks.

In the last few months of the war, Stewart and his comrades fought near Petersburg and in the Appomattox Campaign in Virginia. Stewart, however, suffered severe diarrhea in the trenches in Petersburg, which excused him from active duty. Instead, he served as a mess cook assistant. In May 1865, the regiment was sent to a final assignment in Texas along the Rio Grande River as part of the XXV Corps, an all-black unit stationed along the border with Mexico to challenge French control of that nation. Some black soldiers actually crossed the Rio Grande to fight with troops loyal to Mexican President Benito Juarez. While in Texas, Stewart contracted rheumatism, a fate many soldiers experienced.  In November 1865, the 29th Infantry disbanded.

Stewart moved back to Wisconsin and married Elizabeth “Eliza” Thornton on October 25, 1868, in Logansville. The couple had one son, Vay, a year later in 1869. Stewart lived and worked as a lumber laborer in Peshtigo, Wisconsin, until he and his family