Miller has worked for Democratic U.S. Senator
Robert Menendez, as well as the
2004 Kerry and the
2012 Obama presidential campaigns. and served as the spokesman for
U.S. Attorney General Eric Holder. After the
2020 U.S. presidential election, Miller was part of the
Biden presidential transition. During the early days of the
Biden administration, he led the efforts to get
Antony Blinken's nomination as
U.S. Secretary of State confirmed. In 2022, he coordinated communications efforts regarding
Russia's invasion of Ukraine for the
U.S. National Security Council. A
deepfake created using spliced footage from multiple press briefings of Miller saying
Belgorod was an appropriate target for Ukrainian strikes and that the city had been evacuated circulated in May 2024; he denounced the deepfake as "disinformation".
Voice of America described the deepfake as having hallmarks of the
Russian information war against Ukraine. Miller was banned from Russia in retaliation for American sanctions on Russians and his role in outlining American foreign policy. He expressed concerns about Chinese support for the war and condemned Chinese military drills near Taiwan following a speech by Taiwanese president
Lai Ching-te and Chinese withdrawal from arms control talks following American arms sales to Taiwan. Miller served as the spokesperson during and after the
October 7 attacks and the subsequent
Gaza war. Miller said "too many innocent Palestinians" had been killed following injuries and deaths at an aid site in February 2024 and called for Israel to increase the flow of aid to Gaza. He called for a full investigation into August 2024 allegations of sexual assault of Palestinian prisoners by
Israel Defense Force (IDF) members and condemned a strike by the IDF on a building in the
Gaza Strip that killed at least 55 people in October 2024, calling it "a horrifying incident with a horrifying result". The same month, Miller said Israel's efforts to resolve humanitarian issues in Gaza had been insufficient. in Israel on October 22, 2024 Miller was accused of inappropriate levity when discussing the Gaza war by
Sam Husseini and
Matt Lee, with the former accusing Miller of smirking when talking about the war's death toll. Miller denied the accusation. In response to a question about aid failing to reach Gaza citizens, Miller said that Israel had failed to properly facilitate its transfer, but that the evaluation period was 30 days and it "wasn't the end of the semester", drawing a rebuke from Lee.
Mark O'Connell criticized
Biden administration spokespeople generally and Miller specifically in
The Irish Times, writing that Miller's "apparent disregard" for the people in Gaza led to his levity. Miller later said he was referring to specific remarks made by Albanese in 2022 regarding a "Jewish lobby controlling America", reported by
The Times of Israel. In September 2024, he said that the United States has always been "committed to the destruction of Hamas" while also seeking a "diplomatic resolution to conflict in the Middle East".
Current Affairs editor-in-chief
Nathan J. Robinson called the position self-contradictory, as Hamas is a party in the conflict. In discussing the death of Kamel Jawad, an American killed in the
2024 Israeli invasion of Lebanon, Miller said it was the State Department's understanding that Jawad was a
legal permanent resident rather than a citizen. This was criticized by the
Council on American–Islamic Relations. Miller subsequently said the Department was examining its records to confirm his citizenship, and it later confirmed he was a citizen. He credited incoming members of the
second Trump administration for their assistance negotiating a ceasefire in the conflict. In a 2025 interview with
Sky News, Miller described recognition of
Palestine by European countries and the
2024 pro-Palestinian protests on university campuses as "appropriate", and stated belief that the
Biden administration could have done more to pressure the Israeli government to agree to ceasefire. Miller also stated "without a doubt" that Israeli soldiers are guilty of
war crimes in the Gaza war. However, Miller also believed that a
genocide was not being carried out in Gaza. In August 2025, Miller said that the Israeli government had sabotaged the
ceasefire agreement on multiple occasions.
Post-Biden administration (2025-present) Following the end of the Biden administration, Miller returned to work as a partner at the
Tucker Eskew founded consulting and public relations firm
Vianovo. Miller had worked at Vianovo for over a decade prior to his tenure in the State Department. ==Personal life==