In a field of 2020 Democratic presidential candidates with no shortage of money, Sen. Kamala Harris and her husband stand out. The California Democrat and her spouse, lawyer Douglas Emhoff, reported about $1.9 million in adjusted gross income for last year, according to tax returns released earlier this year. Their 2018 haul more than doubles the next-highest earning candidate in the 2020 primary field, out of those who have released returns. Former Vice President Joe Biden, who reportedly has made millions since leaving office in 2017, has not yet released his returns. Politicians often rack up huge incomes during and after their time in office. Harris' tax returns show an official whose financial success jumped along with her influence on the national stage — and put her among the top earners in a crowded field trying to prove its chops on working-class issues. [CNBC is looking at how top 2020 presidential candidates accumulated their wealth. Read more about how Bernie Sanders became a millionaire.] Like Sanders and some other rivals, Harris finds herself in the awkward position of a high-income candidate campaigning on helping the low-income Americans they say the economic system has abused. "Working families need support and need to be lifted up. And frankly, this economy is not working for working people," Harris said at the first 2020 Democratic primary debate last week. She promised to repeal the 2017 Republican tax bill, saying it "benefits the top 1%" of earners and "the biggest corporations in America."

Democratic presidential candidate Sen. Kamala Harris (D-Calif.) speaks during the second night of the first Democratic presidential debate on Thursday, June 27, 2019, at the Arsht Center for the Performing Arts in Miami. Al Diaz | Miami Herald | Getty Images

In a statement, Harris campaign spokesman Ian Sams said the senator's agenda shows she is "committed to lifting up average Americans." He highlighted her plans to give a tax credit of up to $500 a month to working families, raise teacher pay by an average of $13,500, transition to a universal health-care system and close the gender pay gap. "She is motivated by the thought of people up at 3:00 in the morning trying to make it all work. Her agenda is meant to address their needs and improve their lives," Sams said. Harris was not always as rich. When she was district attorney for San Francisco (starting in 2004) and then the state of California (beginning in 2011), Harris herself typically made between $125,000 and $225,000. Her household income skyrocketed when she and Emhoff — then a partner at the law firm Venable — married in 2014 and filed their taxes jointly. They reported about $1.2 million in adjusted gross income that year. Harris on her own has raked in more money since she jumped on to the national stage with her 2016 Senate election win. The senator reported making $157,000 from her job in Congress last year. Like her presidential rivals, Harris' biggest cash haul came from writing. She reported $320,000 in net income from her memoir, "The Truths We Hold," which came out in January. Emhoff, now a partner at law firm DLA Piper in Los Angeles, made even more than Harris. He took in about $1.5 million last year. Emhoff, who has an intellectual property focus, has represented clients including movie studios, former athletes and wine companies. On a separate 2018 Senate financial disclosure form, Harris says the couple had between $2.5 million and $5.8 million in assets. They mostly held the wealth in mutual funds, along with bank accounts and retirement plans. Harris also listed between $2.8 million and $3.6 million in liabilities for the couple in the form of mortgages, home equity lines of credit and a commercial loan.