Klain, 61, became the White House chief of staff in January 2021 after serving in the same role for Biden at the start of his vice presidency.
In his letter, Klain noted that he first became a Biden staffer 36 years ago, when Biden was a senator representing Delaware. Klain recounted that his first day on the job was the day after his honeymoon.
“Leaving and returning to your staff several times since, my work for you has defined my life, both personally and professionally,” Klain wrote.
“In good times, you were the first to call when each of my children was born — and decades later, the first to congratulate me when they got engaged,” Klain said. “In bad times, you were the first to console me when my father passed away years ago, and over the past two months, you have supported me in spending time away from the White House with my ailing mother.”
Klain closed his letter by noting that Biden would have his unflagging support going forward.
“If you choose to run in 2024, I look forward to doing whatever I can to help your campaign, as I did for you in 1988, 2008 and 2020 campaigns,” Klain said. “I will always be a Biden supporter and advocate in whatever I do next.”
Biden, in a statement issued Friday, confirmed reports that he has tapped Jeff Zients, a management consultant who oversaw the administration’s coronavirus response, to replace Klain as White House chief of staff.
Biden said the White House would host an “official transition event” next week to thank Klain for his work and welcome Zients back to the White House in his new role.
“I’m confident that Jeff will continue Ron’s example of smart, steady leadership, as we continue to work hard every day for the people we were sent here to serve,” Biden said.
Zients left the White House in April after steering the administration’s pandemic response and leading the largest vaccination campaign in U.S. history. He returned to the White House in the fall to help Klain prepare for staff turnover after the midterms — a project that was ultimately limited in scope, as few senior staff members have left across the administration.
In his statement Friday, Biden offered profuse praise for Klain, calling him “a once-in-a-generation talent with a fierce and brilliant intellect” as well as someone with “a really big heart.”
Read More: Exiting White House, Klain offers to help Biden if he runs in 2024