The former Smallville actor appeared in court on Wednesday for her sentencing hearing. She had pleaded guilty to charges of racketeering and racketeering conspiracy.
“I made choices I will forever regret,” she said during the hearing at a Brooklyn federal court, also telling the judge she was filled with “remorse and guilt”.
Under advisory sentencing guidelines, Mack faced between 14 and 17.5 years behind bars. She was expected to seek credit for cooperating against NXIVM leader Keith Raniere and taking responsibility for helping him create a secret society of women who were branded with his initials.
Her defence team had argued in court papers ahead of Wednesday’s sentencing that probation or a sentence to home confinement would be more appropriate. Prosecutors had agreed that any prison term should be below the guidelines range due to her cooperation in the case.
In a letter filed to the court last week, Mack had apologised to “those of you that I brought into NXIVM”, adding: “I am sorry I ever exposed you to the nefarious and emotionally abusive schemes of a twisted man.”
She also described her loyalty and devotion to NXIVM leader Keith Raniere as “the biggest mistake and greatest regret of my life”.
Mack reiterated her apologies to the victims in court on Wednesday, stating: “From the deepest part of my heart and soul, I am sorry.”
She wept at times while reading her statement to the court. US District Judge Nicholas Garaufis told her he believed her apology was sincere, but said she deserved a serious sentence for becoming "a willing and proactive ally" of Raniere.
Raniere was sentenced last year to 120 years in prison after being convicted on charges including sex trafficking and racketeering.
Mack, 38, was once part of the inner circle of Raniere, whose group attracted millionaires and actors among its members. Prosecutors said she became a “master” for “slaves” she ordered “to perform labour, take nude photographs, and in some cases, to engage in sex acts with Raniere”.
According to government papers, Mack eventually provided information to prosecutors about how Raniere encouraged “the use of demeaning and derogatory language, including racial slurs, to humiliate” people referred to as “slaves” within the organisation.
More importantly, she provided a recording of a conversation she had with Raniere about a brand of his initials that was performed on some members, the government papers added.
The branding should involve “a vulnerable position type of a thing” with “hands probably above the head being held, almost like being tied down, like sacrificial, whatever,” Raniere told her. The women, he added, “should say, ‘Please brand me. It would be an honour.’ Or something like that.”
Mack has been told to surrender to prison on 29 September.
The Associated Press contributed to this story