Jurors deliberated for 6 1/2 hours over two days before sentencing Mauldin. They also fined him $10,000.
Mauldin was teary-eyed after hearing the sentence. His mother, Joanie, loudly sobbed in the courtroom after the verdict was read.
Relatives of the little girl were set to read victim impact statements in court, where they would tell Mauldin how the crime has affected their lives.
Prosecutors had wanted Mauldin to be sentenced to the maximum life in prison.
Just before putting her in the Galveston hotel-room microwave, Mauldin had punched the then 2-month-old child and placed her in the room's safe and refrigerator.
Mauldin's attorney had asked jurors to consider his client's long history of mental illness and sentence him to probation so he could be treated at a hospital.
Prosecutors said Mauldin hurt his daughter because was angry that he was in a loveless marriage.
They also said Mauldin had a history of violence and of lying about being mentally ill to get out of trouble.
But defense attorney Sam Cammack III said Mauldin has been wracked by mental illness since he was 10.
Mauldin claimed he started hallucinating when he was left alone in the hotel room with his daughter, feeling like mud was running up his body and consuming him.
When Ana was injured, Mauldin and his family had just moved to Galveston, about 50 miles southeast of Houston, from Warren, Ark., so he could become a preacher.
Mauldin at first told police his daughter had been severely sunburned, later changing his story and saying he had accidentally spilled hot water on her while making coffee.
Joanie Mauldin pleaded for mercy, saying her son did not know what he was doing.
Michael Fuller, a psychiatrist who examined Mauldin, testified he could not conclude Mauldin was insane at the time of the crime.
However, Fuller said he believed Mauldin suffered some form of mental illness, but is not violent and would benefit from receiving treatment outside of prison.
Ana suffered second- and third-degree burns to her left ear, cheek, hand and shoulder and required two skin grafts. Part of her left ear had to be amputated.
The girl's foster mother, Heather Croxton, told jurors Ana, now 1, screams during the daily process of cleaning the wounds, and endures physical therapy five days a week. She lives with Croxton and her family in College Station.
Croxton, whose husband is a step-cousin to the girl's mother, Eva Mauldin, said she hopes to adopt Ana.
A trial to terminate the Mauldins' parental rights is scheduled for April.
Eva Mauldin refused defense attorneys' requests to testify and lives in Arkansas.