Oliver Corney,Â of Garden Street, Mexborough pleaded guilty to possession of a stun fun and laser, as well as harassment and assault.
The 28-year-old was sentenced to 34 months imprisonment at Sheffield Crown Court on Wednesday September 12.
Investigations Officer Amy Fourlis said: 'I am pleased that Corney has been jailed for his vicious behaviour.
'In March this year, not only did he assault his victim, he also threatened her with a stun gun and said that he would shatter her jaw.
'He continued to harass and threaten her, putting her through a terrible ordeal and causing significant distress.
'Violent and threatening behaviour in any form will not be tolerated and as this case shows, you will be put before the courts and you will face jail.'