After graduating from Rhodes, Beaumont joined the management of the
Democratic Alliance (DA), South Africa's largest opposition party. He served as the managing director of the party's
KwaZulu-Natal branch and then of its
Gauteng branch. During Mashaba's first year in office, Beaumont's government salary was increased from
R1.3 million to R1.8 million per annum, and the
African National Congress complained that the increase had been effected irregularly and at Beaumont's instruction, in a "flagrant
abuse of power". Mashaba's spokesman denied any impropriety. Mashaba resigned from the DA and his mayoral office in November 2019, citing disagreements with the DA's national leadership, and Beaumont resigned with him. In 2020, he published
The Accidental Mayor: Herman Mashaba and the Battle for Johannesburg, a book about Mashaba's mayoral term based on Beaumont's diaries. == ActionSA: 2020–present ==