This study traces the distinct stages of formation and activities of Alexander Macmillan, an iconic figure in the Jehovah's Witnesses religious movement. Born into a Protestant family affiliated with the Presbyterian Church, Macmillan developed an early interest in spiritual matters, ultimately leading to the establishment of the Bible Students-a precursor to the present-day Jehovah's Witnesses organization. Throughout his life, Macmillan gained prominence and historical respect through his close collaboration with the organization's first three presidents: Charles Taze Russell, Joseph Rutherford, and Nathan Norra. Motivated by events during his formative years, Macmillan embarked on a missionary path, attending the school of renowned Protestant evangelist Dwight Moody. It was during his studies that he encountered representatives of the International Bible Students, notably their founder and leader, Charles Taze Russell. Intrigued by the organization's ideas and teachings, Macmillan joined the religious movement and dedicated his life to it, emerging as a fervent missionary who spread the doctrines of Jehovah's Witnesses through preaching travels. This study highlights key factors contributing to Macmillan's recognition in Jehovah's Witnesses history, positioning him as a central figure in the religious movement. The first factor is his proximity to and trust from the organization's early leaders. The second is his active missionary work and steadfast commitment to disseminating the movement's doctrines and teachings. The third factor is Macmillan's imprisonment alongside other organization leaders for their religious views, an experience that solidified his authority among believers and made him a symbol for Witnesses facing similar life circumstances.