William is a third generation Polish American, born on August 11 (or 15), 1911, in the United States. He is the grandson of a Polish immigrant, and the son of Rip Blazkowicz, an ambitious, but crooked and racist Polish-American con-artist and businessman; and Zofia, a young Polish Jew. He grew up on a farm called the Blazkowicz Estate in Mesquite, Texas, near Forney Lake, in the 1900s. His childhood was abusive, with his father venting his anger on him, his mother, and their dog Bessie for his failing business. He would also lock B.J. in the closet when he was bad, where he would lose track of time
At a young age, B.J. started to have nightmares, often waking his father in the middle of the night. This ended when his father took him in the basement to fight the monsters with weapons, curing B.J. of his nightmares. His father later gave him his pocketknife; it was later taken by bullies Andy and Howie, with B.J forced by his father to get it back himself if he wanted to ever enter the house again. B.J. was also forced by his father to get his pocket watch from the well, something that is recollected in his memories upon his return to the well in 1961. Despite the abuse he suffered from his father, his mother showed him unyielding compassion, and she trusted him with her engagement ring, a family heirloom for B.J. to give to his spouse one day
Around the age of nine or ten, B.J. met and befriended an African American girl named Billie, whom he developed a mutual crush on. She would have a great impact on his morality, as he saved a rat he put into a bucket full of water due to her pleas. However, they were caught by his father under the poplar tree, enraging him. His mother hid him and Bessie in the closet while she dealt with Rip. Rip and Zofia argued until he slapped her unconscious, leading B.J. to come out of the closet and unsuccessfully throw vases at his father until B.J. was strangled unconscious. Later that day, B.J was strapped to the sawhorse in the basement, and forced to shoot his dog Bessie, much to his father's glee; however, depending on the player's actions, Bessie is shot by Rip when B.J. misses her. Afterward, B.J. and Zofia buried Bessie in the front yard, while B.J. was consoled by his mother, who told him it would end better than it began. He was then taken into his room, where his mother noted that Rip hurt him badly, asking him whether he wanted soup or porridge
B.J. once swam in the Gulf during Red Tide, despite his father's command not to, causing his skin to burn. At age 11, he swam across Forney Lake on a dare for tin soldiers. At age 13, he fell into a pond near his family's stable and was covered in leeches. At age 19, he fell into the family well, in order to try to salvage his father's watch. Despite the many hardships, he remembered some good times, such as seeing Mesquite at sunset, and the country music he used to play back home. He later went to work for his cousin, where he earned his first dollar. He also spent time with his grandmother, where he learned that his Aunt Sara was diagnosed with dementia during her time in college. B.J. notes that she was given medication, but it made her drowsy and strange. His grandmother told him it passed through the blood, and he noted that her eyes were like dirty windows on a derelict shack
Once B.J. reached the right age, he ran away from home and joined the United States Army, much to his father's chagrin, and to his mother's heartbreak. In the army, he joined the Army Rangers and was sent to boot camp, learning to kill Commanders first to not let reinforcements come into the battle. B.J. would later join the OSA and befriend fellow agents Richard Wesley and Pippa Shepherd. Around the same time, B.J. also befriended Wing Commander Fergus Reid, who referred and nicknamed him "Blazko
At age 32 (c. early 1944) (a bit older than he actually was in RTCW, a retcon to the dating of the event), he traveled to Deathshead's X-Labs, swimming through the cesspools to destroy the super soldier research and the base
