Marshall Tricklebank was sentenced to nine years and five months in prison after pleading guilty to harassment, aggravated burglary, and possession of an imitation firearm with intent to cause fear or violence.
The 20-year-old Ticklebank, of Broadstone Road in Birmingham, was also given a restraining order prohibiting him from any contact with the victim or her family until further notice.
Tricklebank had been in a brief relationship with the victim, but became controlling, coercive and abusive, both mentally and physically, West Midlands Police said.
After she broke up with him, he made threats to the victim and her family, including threatening to burn their house down with three young children inside.
On one occasion, on May 16, he threatened her mum with an imitation firearm and forced her to withdraw £600 from a cash machine, which she did in the hopes of him leaving her daughter alone for good.
Two weeks later, Tricklebank shot her step-father in the neck with a high-powered BB gun and was arrested after being found hanging from the upstairs window, armed with a knife. The imitation firearm was later recovered from his home and used in evidence.
Detective Constable Jay Aston, who carried out the investigation, said: "This was a really traumatic and distressing experience for the victim and her family.
"We are glad that justice has now been done and that they have a measure of protection and reassurance.
"Tricklebank had lots of opportunity to leave them alone, but he chose not to and even threatened to kill them if they got the police involved.
"The family were so convinced that he would hurt them that they didn’t tell anyone what happened at first.
"I would like to thank them for their bravery and courage for speaking out and supporting the case through to conviction. I want others to know that we will always give support to victims.
"Securing the best evidence to enable us to get such cases to court can be very challenging but we are committed to doing so.
"The severity of the sentence indicates the seriousness of his actions. Behaviour like this will not be tolerated and will be punished heavily.
"Anyone undergoing such a distressing experience can contact us at any time, to talk in confidence, and to secure access to further specialist advice and support."