A reporter for the Chicago Record (1892–98), Baker became associated with Outlook, McClure's, and the “muckraker” American Magazine. He explored the situation of black Americans in Following the Color Line (1908). As David Grayson he published Adventures in Contentment (1907), the first of his several collections of widely read essays. From 1910, when he first met Woodrow Wilson, Baker became an increasingly fervent admirer. At Wilson's request, Baker served as head of the American Press Bureau at the Paris peace conference (1919), where the two were in close and constant association. Despite prolonged ill health, Baker wrote Woodrow Wilson: Life and Letters, 8 vol. (1927–39). He was awarded the Pulitzer Prize for the work in 1940.