Sir Philip Bailhache, then Jersey's attorney general, supervised Roger Holland's appointment to the honorary police in 1992.
Holland had been convicted of sexually assaulting a 14-year-old girl with learning difficulties in 1986, when he worked for St John Ambulance.
Sir Philip said he had not known before Holland's inauguration.
Holland was jailed for two years in 2008 for eight sexual offences, some of which were committed while he was in the honorary force.
Despite including the 1986 conviction on his application form, he was elected to the St Helier honorary police in 1992, where he held office for another six years.
Sir Philip said he was only informed of Holland's conviction after the election, and "it was reasonable to conclude he had been re-habilitated".
"What Holland did was put his hand up a girl's pullover. It was an unpleasant thing to do but across the range of sexual offences it was at the lower end of the scale.", he said.
The Jersey Care Inquiry is investigating allegations of child abuse in Jersey's care system since 1945.
Sir Philip, Jersey's current external relations minister, also denied he deliberately distracted attention from abuse victims in a speech he gave in 2008.
He told people on Liberation Day :"All child abuse is scandalous but it is the unjustified and remorseless denigration of Jersey and her people that is the real scandal."
Sir Philip told the inquiry he was not "diminishing the gravity of child abuse" but that his choice of words were possibly "unfortunate".
A former senior judge was "not aware" a man was a convicted sex offender when he was admitted to a voluntary police force, an inquiry has heard.