On returning to civilian life, Agate pursued his career as a theatre critic. In 1919 he published a second book of essays, "Alarums and Excursions". In 1921 he secured the post with "The Saturday Review" once held by Shaw (and then by Max Beerbohm), and in 1923 he moved to "The Sunday Times", where he remained theatre critic for the rest of his life. From 1925 to 1932 he combined his newspaper work with the post of drama critic for the British Broadcasting Corporation. His former paper, "The Manchester Guardian", later wrote of him, "That Agate was the first dramatic critic of his time may well be doubted by adherents of Ivor Brown or Desmond MacCarthy, but beyond dispute he was the first theatrical critic. He was native to the theatre, he understood acting, he had in his blood both the French... and English stages."