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 further 26 people were injured when the two-storey factory, under construction in the Sao Mateus neighbourhood, collapsed.
Two of the 36 people who are believed to have been working in the building at the time are still unaccounted for.
It is not yet clear what may have caused the collapse.
According to city officials, the construction work did not have the necessary permits and two fines had been issued already in relation to the work carried out.
Edilson Carlos dos Santos, a lawyer for the owner of the site, blamed the engineering company hired to work on the building for the collapse.
Mr Santos said the company, Salvatta Engenharia, had been installing lift shafts and staircases at the time of the collapse on Tuesday.
The engineering company denied the allegations, saying in a statement that it had not yet received the keys to the building "because the works he [the owner of the site] had agreed to carry out had not been completed".
Some 60 rescue workers continue to search the site with sniffer dogs.
They dug holes into concrete walls with sledgehammers and removed metal sheeting in their attempt to find the missing construction workers.
Building collapses of this kind are common in Sao Paulo - Brazil's largest city - and particularly affect structures that are either poorly maintained or still under construction.
Home to 11 million people, Sao Paulo is one of 12 Brazilian host cities for next year's World Cup.
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.
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Firefighters searching the rubble of a collapsed building in the Brazilian city of Sao Paulo have found another body, taking the death toll to eight.