A jury found 27-year-old Stetson Tedder guilty of domestic violence child assault and unlawful imprisonment.
The Daily Herald reports the girl was covered in dozens of welts and had scars on her wrists and ankles, apparently from being bound with zip ties.
Snohomish County Superior Court Judge George Bowden gave Tedder a sentence in the middle of the possible range.
The judge noted Tedder was an Air Force veteran who served in Iraq and had no criminal history. The judge noted the girl's tender age but also said, "The reality is children don't come with operation manuals."
Documents filed in Snohomish County Superior Court say the pain inflicted on the girl was "the equivalent of that produced by torture."
Tedder bound the girl with zip ties and duct tape, then shot her at least three-dozen times with plastic pellets until her skin looked like chicken pox, court documents say.
The case came to light when the little girl's grandmother noticed red dots all over her body and asked the girl what had happened.
The girl told her grandmother that Tedder had hog-tied her and shot her with a pellet gun, and that she had cried from the pain, court documents say.
The grandmother took the little girl to Providence Hospital in Everett, where she was examined. Her grandmother and hospital staff counted more than 36 marks on the little girl's body.
The girl told detectives that Tedder became angry when she woke him up early, so he shot her with the pellet gun, according to documents filed in Snohomish County Superior Court.
On another occasion, the girl said, Tedder tied her up after her room was messy and made her pick up her room with her teeth, court documents say.
Court records also say Tedder admitted to detectives that he used duct tape to hog-tie the little girl as a form of punishment for up to 30 minutes.
The girl told police that her mom left the house when Tedder was shooting at her with the gun because "she doesn't want to hear her cry," court documents say.