Luke Merry was arrested after the screening was interrupted when a seven-year-old jumped on to her chair in fright after her leg was grabbed.
The lights were turned on at Vue Cinema, Kirkstall, and Merry was found laying on the floor close to where he had assaulted the two girls.
Merry's mobile phone was seized and found to contain footage he had taken in the female toilets at the Vue Cinema, Sheffield.
Merry had secretly filmed a child's feet under a cubicle as the youngster used the toilet.
The 25-year-old was jailed for 18 months today after pleading guilty to two offences of sexual assault of a child under 13 and one of voyeurism.
Daniel Penman, prosecuting, described how Merry touched two female children as they watched Dumbo with their parents at the Kirkstall cinema on April 13 this year.
A six-year-old girl complained to her mother as she felt a "hairy arm" against the back of her calf and feared she was going to be pulled under the seat.
The youngster was scared and became tearful.
The prosecutor said the victim's sister felt "sick, confused and disgusted."
The second victim jumped onto her chair and then into her mother's lap after feeling a hand against her leg.
The parent looked under the seat and saw a flashing light and a "boney hand."
Merry was found on the floor when the lights were turned on by cinema staff.
The defendant, who has hearing difficulties, claimed he had dropped his ear piece and had got down to look for it.
Investigations revealed Merry had been to see the same film twice in the week before the incident at cinemas in Castleford and Sheffield.
During interview he told officers he had travelled to Leeds from his home in south Yorkshire to watch the film because he "liked Dumbo".
Merry, of Lakeside Boulevard, Doncaster, changed his account of the incident after initially denying touching anyone.
He then admitted the offences but claimed he believed he had been touching adults.
Merry told officers he been on the floor looking for his earpiece then "became aroused."
At the time of the offences, Merry was the subject of a community order for outraging public decency after he was arrested for committing a sex act while under a computer desk at a college campus in Nottingham.
Merry had previously been banned from the The Vue in Sheffield for climbing under the seats during a screening of How to Train Your Dragon.
On a further occasion he was arrested for going under a table at a library.
Victim statements were read to the court on behalf of the parents of the two victims.
One of the children had been too scared to sleep in her own bed after the ordeal as she was afraid someone would be hiding beneath it.
She had also been too scared to go to the cinema since the incident.
The father of the other girl said his daughter had also been traumatised by what had happened.
He said: "You hear about weird people being around but until it happens to you, you can't put into words how it affects you as a father."
The court heard Merry has been assessed by a psychosexual therapist, who described him as being "truthful" about having a foot fetish.
A probation report assessed Merry as posing a high risk of further offending.
Robin Frieze, mitigating, said Merry had the support of his parents and has been receiving help to address his offending from an organisation called Stop It Now.
Mr Frieze said Merry committed the offence due his foot fetish and not because he was sexually attracted to children.
He said: "It's not children - it's feet.
"That in my opinion is a distinctive feature of this case."
Jailing Merry, Judge Simon Phillips QC said: "These girls and their families have been traumatised by your deliberate actions.
"Those consequences were entirely foreseen.
"You travelled significant distances from your home in order to commit these offences.
"There was a degree of determination to obtain sexual gratification from your fixation with female feet."
Merry was also told he must go on the sex offenders register for ten years.