Julian Hobbs was convicted of a series of sexual offences against a girl in Barry following a trial in December.
The jury found Hobbs guilty of three offences of rape of a child, as well as causing a child to engage in sexual activity and causing a child to watch a sexual act.
Prosecutor James Wilson said Hobbs raped a girl who was aged between four and six years old and promised her a bag of sweets if she did as he said.
Hobbs also showed her images of couples having sex – including of himself having sex with a woman.
The offending came to light in April last year after the child disclosed the abuse.
Newport Crown Court heard Hobbs had threatened to “slap or punch” the girl if she told anyone about the abuse.
In a statement read to the court by Mr Wilson, the victim’s mother said her daughter had “turned into a really private young girl” and had “become closed off” as a result of the abuse.
However, she said a weight had been lifted off her daughter’s shoulders now Hobbs had been found guilty.
“She knows she’s done the right thing by speaking out,” her mother said.
“We are all amazed how brave she’s been by speaking out.”
Hobbs, of Brithdir Street in Cardiff, had denied the offences, but was found guilty on December 18.
The 36-year-old defendant had 10 previous convictions for 28 offences – including for violence and harassment.
“He’s got previous convictions that do not help him, but they are not for sexual matters,” said Harry Baker, in mitigation.
Addressing the judge, Mr Baker added: “I would ask you to keep the sentence as short as possible.”
Judge Daniel Williams sentenced Hobbs to 15 years imprisonment, with a further three years extended licence period.
Hobbs must serve two-thirds of the 15-year sentence before the parole board can consider whether it is safe for him to be released.
He was ordered to register indefinitely as a sex offender.
The case will return to court on March 23 to consider if a restraining order and a sexual harm prevention order will be imposed.
