[2] Baker was educated at Corpus Christi College, Oxford, United Kingdom and holds a degree in Philosophy, Politics and Economics (first class honours).

[8][3] As deputy editor-in-chief, Baker (then serving under Robert Thomson) replaced Journal reporters and bureau chiefs who they felt were too liberal.

"[10] In 2009, a year after their appointment, Thomson and Baker were reported to have given the newspaper a more conservative outlook and, according to David Carr of The New York Times, their editing reflected "a chronic skepticism of the" Obama administration.

[12] As editor, Baker mourned the death of Journal reporter David Bird, who had been missing and whose body was later found in a river.

In 2016 and 2017, the Journal leadership under Baker was criticised, both from the outside and from within the newsroom, who viewed the paper's coverage of President Donald Trump as too timid.

[12] Particularly controversial was the Journal's November 2016 front-page headline that repeated Trump's false claim that "millions of people" had voted illegally in the election, without reporting his statement was inaccurate.

[12] Also controversial was a January 2017 note from Baker to Journal editors, directing them to avoid using the phrase "seven majority-Muslim countries" when writing about Trump's executive order on travel and immigration; Baker later sent a follow-up note "clarifying that there was 'no ban'" on the phrase, "but that the publication should 'always be careful that this term is not offered as the only description of the countries covered under the ban.

In May 2020, a column written by Baker in the wake of the murder of Ahmaud Arbery,[21] which argued that the news media failed to report crimes committed by black people against whites, was criticized in a letter sent by the Independent Association of Publishers' Employees, the union representing Journal reporters, for violating rules that apply to the news division.

[26] In a separate article, New York Times columnist Nicholas Kristof referred to the column as right-wing fearmongering.