Harris’s Brother-in-Law, a Corporate Executive, Emerges as a Close Adviser

Vice President Kamala Harris had a secret weapon on hand as she worked the phones in the hours after President Biden dropped his re-election bid and endorsed her.

Tony West, her brother-in-law and the chief legal officer at Uber, was with Ms. Harris in the vice president’s residence when she received the news, and he spent the afternoon helping her reach out to would-be supporters. At various points he peeled away to a nearby anteroom to call his own network of donors and business contacts, after which the two relatives compared notes, someone familiar with the matter said.

Since that Sunday, Mr. West has emerged as a major force behind Ms. Harris’s campaign and its record-setting fund-raising, but also as a concern for some progressives who want her to take a hard line against big business. He is expected to remain involved in the final 92 days of the race, with Uber announcing on Friday that Mr. West would soon take an unpaid leave of absence to focus on the White House run.

Ms. Harris’s campaign brought on several senior political operatives on Friday, some of whom worked on former President Barack Obama’s campaigns, to add to the team that had been assembled to re-elect Mr. Biden. But none has the advantage of family ties like her brother-in-law, who has held top positions in the Justice Department and corporate America while advising Ms. Harris’s campaigns since she ran for San Francisco district attorney in 2003.

And Mr. West, who is serving as an unpaid adviser, has already made a mark on her campaign.

He recommended bringing on Eric H. Holder Jr., the former attorney general, to handle the vetting process for Ms. Harris’s running mate, said the person familiar with the matter, who requested anonymity to discuss