The resignation comes amid a decision by company shareholders who pushed for his exit.
"I love Uber more than anything in the world and at this difficult moment in my personal life I have accepted the investors request to step aside so that Uber can go back to building rather than be distracted with another fight," Mr. Kalanick said in a statement.
Already before his resignation, Kalanick last week announced that he would be taking an indefinite leave of absence that he said would give him time to work on becoming a better leader. He also said that he needed the time away to grieve the loss of his mother, who died in a boating accident less than a month ago.
While Kalanick launched Uber into one of the world's most ubiquitous companies, his tenure has been marked by a number of controversies.
Holder, now a partner at the law firm Covington & Burling, was tapped by the company to conduct a review of the company's workplace environment after a former employee alleged that she had been sexually harassed and discriminated against while working there.
About 20 employees were fired as a result of that investigation, according to the company.