Attorney General Jeremy Wright will not refer the disgraced entertainer's sentence of five years and nine months to the Court of Appeal, a spokeswoman in his office said.
Mr Wright's decision comes despite his office receiving 150 complaints about the leniency of Harris's sentence, of which he will serve half, although it only takes one complaint to trigger the review process.
Harris, 84, a family favourite for decades, was finally unmasked as a prolific paedophile following his conviction for 12 indecent assaults at the end of last month.
A spokeswoman for the Attorney General's Office (AGO) said: "The Attorney General understands that his decision not to refer the case may be a disappointment to some people; however, he did give extremely careful consideration to this sentence and he concluded that he could not refer it."
She added: "After very careful consideration, the Attorney General, Jeremy Wright QC MP, has decided not to refer the five year and nine month sentence given to Rolf Harris to the Court of Appeal, as he did not think they would find it to be unduly lenient and increase it.
"The sentencing judge was bound by the maximum sentence in force at the time of the offending.
"The judge made some of the sentences consecutive to reach the total sentence, but he could not simply add up sentences on individual counts; the overall sentence had to be just and proportionate to the overall offending.
"The judge was also required to take into account the age of the offender."
Harris was unanimously found guilty of molesting four girls - one woman who was just seven or eight and was groped when she asked for his autograph, and another two who fell prey as young teenagers.
The veteran presenter, who charmed television audiences for decades, was also convicted of a catalogue of abuse against his daughter's then-best friend, who prosecutors said Harris groomed from the age of 13 and used like ''his little toy''.
The accusations dated between 1968 and 1986, and the girls were targeted between the ages of seven or eight and 19.