The Blind Side star revealed in April (10) that she and her then-husband Jesse James had secretly welcomed the tot into the family in January (10).
She subsequently split from the TV mechanic in March (10) when his infidelities were exposed in the press and their marriage was officially declared over in June (10).
The Oscar winner proceeded with the adoption process as a single parent, moving from California to set up home in Austin, Texas.
And Friday 13th (13Aug10), a traditionally unlucky day, proved to be a joyous occasion for Bullock - a judge at the Jefferson Juvenile Justice Center in Louis' native New Orleans, Louisiana signed off on the adoption papers at a finalisation hearing.
The actress was joined by her friends and family, including her sister Gesine, for the momentous occasion, four years after she began her journey to parenthood.
An eyewitness tells People magazine, "She was happy... She is so in love with her child."