They asked the judge to make Wiltse register as a sex offender as part of the punishment.
The man is described as a relative of the girl, although no further details of the relationship have been given.
The girl came forward with the accusation in 2017, when she was 11.
The girl told police Wiltse woke her up late at night, removed her clothes and touched her inappropriately.
Wiltse pleaded guilty to two counts of indecency with a child by sexual contact and two counts of indecency with a child by exposure.
He has also been told to pay a $2000 fine and perform 240 hours of community service.
He cannot have contact with anyone under 18, unless he has prior approval.