"No drive has more positive ripple effects than the desire to be of service," she wrote.
MacKenzie Bezos, who got more than $35 billion in her divorce to Amazon founder and chief executive Jeff Bezos, said she will donate roughly half of her wealth to charities.
Bezos, 49, became the latest person to join The Giving Pledge, an organization created by Bill and Melinda Gates and Warren Buffett that invites billionaires to commit to donate more than half of their fortune to philanthropy or charitable causes either during their lifetime or in their will.
"No drive has more positive ripple effects than the desire to be of service. There are lots of resources each of us can pull from our safes to share with others — time, attention, knowledge, patience, creativity, talent, effort, humor, compassion," Bezos said in a May 25 letter on the organization's website.
"In addition to whatever assets life has nurtured in me, I have a disproportionate amount of money to share. My approach to philanthropy will continue to be thoughtful. It will take time and effort and care. But I won't wait. And I will keep at it until the safe is empty," she added.
Jeff Bezos tweeted Tuesday morning that his ex-wife "is going to be amazing and thoughtful and effective at philanthropy.
Jeff and MacKenzie Bezos announced the dissolution of their marriage in separate statements last month. The pair, who married in 1993 and have four children, announced their divorce in January.
Bezos, an author and anti-bullying advocate, said she was giving Jeff Bezos all of her interests in The Washington Post, which he owns.
She also said she was going to give him her interests in his space exploration company, Blue Origin, as well as 75 percent of their Amazon stock along with voting control of her shares.
According to a filing with the Securities and Exchange Commission, she will retain roughly 4 percent of Amazon's outstanding common stock, worth about $35.6 billion.
The settlement would make Bezos, who has written two books and founded the anti-bullying organization Bystander Revolution, the fourth-richest woman and the 22nd-wealthiest person in the world, according to Bloomberg Billionaires Index, which profiles the 500 wealthiest people on the globe. Based on the index, Bezos has a net worth of about $36.6 billion.
Jeff Bezos remains the richest person in the world with an estimated net worth of $114 billion. He's followed by Microsoft founder Bill Gates, who once said he will only leave his children a "minuscule portion" of his estimated $102 billion worth. Warren Buffett, who has a net worth of around $83.2 billion, is the fourth-richest person in the world, according to Bloomberg Billionaires Index.