[4] In the 1990s, Newsham was selected by then-Chief Charles H. Ramsey "to oversee a department overhaul after concerns surfaced in the late 1990s over the high number of deadly shootings by officers".

[8] In April 2002, Newsham was reported to have "ordered police officers to cordon off Pershing Park, about two blocks from the White House, after he observed some protesters committing acts of vandalism".

[13] In 2016, Newsham oversaw the investigation of the murder of Seth Rich, noting that there was no information to support internet rumors that the death was connected to WikiLeaks involvement in the 2016 Democratic National Committee email leak.

[5] As Interim Police Chief, one of the first matters to be addressed by Newsham was the investigation of Edgar Maddison Welch for firing shots from an AR-15-style rifle at the Comet Ping Pong pizzeria.

Welch had been convinced by Pizzagate conspiracy theory proponents on the internet that the restaurant was part of a Democratic Party child sex ring.

[17] In January 2017, Newsham oversaw city-wide police preparations for the Inauguration of Donald Trump, with its anticipated high number of protests.

[5] Protester disruptions caused the suspension of his first oversight hearing,[19] and the ACLU recommended delaying the confirmation vote until an investigation was concluded.

[20][21] In defending her nomination of Newsham to be police chief, Mayor Bowser praised his "commitment to transparency" and "“availability to his officers and members of the public",[5] and said she was impressed with the job her nominee did as interim chief, citing the police department's performance during the Presidential Inauguration of Donald Trump and the ensuing Women’s March on Washington on his watch.

[21] On the eve of a confirmation vote by the D.C. council, the Washington City Paper said of the nominee, "He's generally respected by the rank-and-file when it comes to policing, and he has managed to forge his own reputation as a leader despite years of being the main enforcer for former Chief Cathy Lanier, who was not particularly well liked by the rank-and-file", while noting allegations of domestic and alcohol abuse made in the 1990s, and "a professional history stained by a high-profile mass arrest gone bad".

[5] Following a massive gunfight in Northeast Washington in January, 2019, in which more than 40 bullets were fired in front of a barbershop long suspected by police to be an "open-air drug market", activists and D.C. Council members criticized what they called illegal and aggressive searches by officers.

[23] In September 2019, data released by MPD pursuant to a court order found significant disparities among stops by officers.

The Council sought to bring greater accountability, limit the use of force against unarmed civilians, and make it easier to fire officers, among other reforms.

[34] Newsham said police officers "feel they have been abandoned", and that the Council's actions failed to reflect years of reforms within the department, while Councilmembers said he had missed the point of the protests, with members Robert White, Charles Allen, and Vincent C. Gray asserting that his comments were dangerous.

[35] In July 2020, in response to litigation filed in the aftermath of the use of force to clear protesters for the Donald Trump photo op at St. John's Church, Newsham denied that officers in his department were involved in that action.