He added, "I will spend the rest of my life asking for forgiveness."
In January, Schwartz - who worked at GSO Business Management, which boasts famous clients such as 50 Cent, Tom Petty and Sofia Coppola - pleaded guilty to wire fraud and filing a false tax return after admitting to stealing almost US$5 million from Morissette between May 2010 and January 2014 and US$1.7 million from two other clients.
He could have received more than 20 years in prison, and Morissette urged in a victim statement that he be punished harshly.
"He did this in a long, systematic, drawn-out and sinister manner" that could have bankrupted her within three years, Morissette said.
"I'd go on tours he recommended and they would lose money, but he'd still urge me to spend. Spend. Spend. He was creating an alibi from the start."
"He not only stole $5 million in cash from me, he stole a dream," she said, according to Variety, adding that he would cry if she asked questions about her finances, "taking advantage of my empathetic nature".
Last month, in an open letter to the Hollywood Reporter, Schwartz said his crimes were fueled by a gambling addiction he has battled since college and subsequent drug use.
He wrote: "I often turned to drugs to deal with the stress but mostly sought refuge in the world of sports gambling. The spiral I was in was toxic. Winning did not make me feel better but losing was intolerable. If I lost, then I had to make it back and when I lost again, the hole I had dug got deeper and deeper.
"I felt weak and powerless, terrified by my internal demons that I was turning into my father."
He said he is now part of the Gambler's Anonymous program and was 336 days sober on April 11.
Some, though, argued this mea culpa was too little, too late.
"Every expression of remorse he has made and every purported act of self-improvement he has taken occurred only after he realized he had no 'choice' to do otherwise," Assistant US Attorney Ranee Katzenstein said in court papers.
Upon his release, Schwartz will serve three years' probation.