She had one good moment as an anti-death penalty DA and immediately decided to give up:

In California, it was unheard of not to seek the death penalty in a case where a police officer is the victim.

But three days later, Harris announced she would not seek the death penalty against the suspect. It was a lonely position. At Espinoza’s funeral at St. Mary’s Cathedral, with Harris in the front row, Democratic Sen. Dianne Feinstein called for the death penalty for Espinoza’s killer. Behind Harris, scores of mourning police officers rose to their feet and applauded. After the service, Feinstein commented that had she known Harris opposed the death penalty, she probably wouldn’t have endorsed her for district attorney.

And then:

Four years later, Harris found herself at another crossroads on the death penalty. This time, she took the path law enforcement favored. In July 2014, a federal judge ruled that California’s death penalty system was so dysfunctional that it had become unconstitutional. Of the 900 people sentenced to death since the state reinstated the death penalty in 1978, just 13 had been executed. More than 40 percent of the 748 prisoners on death row at the time of the decision had languished there for more than 19 years. This delay and uncertainty “violates the Eighth Amendment’s prohibition against cruel and unusual punishment,” the judge wrote.

. . .

But it could only set a precedent if it wasn’t struck down. It fell to Harris to decide whether to let the opinion stand or appeal it. The timing was tricky. She was up for reelection in four months, and after painstaking work had rebuilt relationships with law officer unions and even won some of their endorsements. Harris chose to appeal.

So like Biden, who also has claimed to be against the death penalty, she's continued to pursue it even when it's completely under her power. Further proof that if there were 100 Democratic senators, there would be 51 Joe Manchins.