Leeds Crown Court heard 18-year-old Alex Beddoes, of Monkhill Avenue, Pontefract, also exposed himself to a man and two other women in Pontefract.
Beddoes, who will be 19 on Monday (January 22), admitted two charges of sexual assault and seven charges of indecent exposure.
Prosecutor, Stephen Littlewood said the first offence happened in August 2016 when Beddoes exposed himself to a woman aged in her sixties while she was in the garden of her home in Pontefract.
The court heard in June 2017 he exposed himself to the same woman while she was in her garden.
Mr Littlewood said in the same month Beddoes exposed himself to a middle-aged man near the racecourse in Pontefract Park.
The court heard that on August 24 2017, a 63-year-old woman was jogging in Pontefract Park when Beddoes started running behind her before sexually assaulting her and exposing himself.
Five days later, Beddoes followed a 28-year-old woman out jogging in Pontefract Park and sexually assaulted her and exposed himself.
On January 10 this year, Beddoes exposed himself to a woman who was walking with her child in Pontefract.
Mitigating, Christopher Morton said Beddoes suffers from attention deficit hyperactivity disorder and has been unable to access medication since he turned 18. Jailing Beddoes for 14 months, Recorder Tom Little told him: “There was an element of targeting and waiting for your victims as they were running around he area of the park.”