Monuzar Hussain Hamza, 34, a stock taker, of no fixed address, followed the four girls, aged between 14 and 15, along Moat Road in East Grinstead around 3pm on 14 February.
He whistled to get their attention and called out to them, and as they turned around, he was exposing himself and acting indecently towards them. The girls shouted back at him in shock and he ran off, returning to a nearby hotel.
The incident was reported to police, and following house-to-house enquiries and CCTV trawls, Hamza was identified as the suspect.
He was arrested within 48 hours and charged with exposure.
Hamza denied the offence in police interview and was remanded in custody ahead of a trial. However, he later changed his plea to guilty after an overwhelming amount of credible evidence was presented to him.
At Brighton Magistrates’ Court on 14 April, he was sentenced to 26 weeks’ imprisonment and ordered to pay costs totalling £442. He was also put on the sex offenders register for a period of seven years.
Detective Constable Paul Hudson, of Crawley Investigations, said: “I’d like to commend the young girls in this case who were quick to report the incident and provide evidence to secure a conviction against Hamza. Upon his release he will be managed by a specialist team who deal with convicted sex offenders.
“His actions were completely unacceptable and this sort of behaviour will not be tolerated – this is reflected by the immediate custodial sentence handed out by magistrates.”