How did anti-immigrant sentiment shape the culture of the 1920s?

Xenophobia in the 1920s was directed at several different groups, including Americans of Italian and Irish descent, as well as those from Eastern Europe, particularly Russia. Fear and hatred of the Irish and Italians stemmed largely from an antipathy toward Catholics, particularly because America was predominantly Protestant.

Many Anglo-Protestant Americans feared that Catholics would be more loyal to the Pope than to the President. That is why popular New York governor Alfred Smith's bid for the presidency in 1928 went nowhere, despite the fact that he was perhaps the most popular governor New York has ever seen: he was elected to that office four times. Nevertheless, when he became the Democratic nominee for president, Smith was accused of being a Papist.

As mentioned above, similar questions of loyalty and trustworthiness were directed toward immigrants of Eastern European extraction, first because their language and foods were considered strange, but also because many were Jewish, and anti-Semitism was rife. Additionally, the Bolshevik Revolution in Russia was still fresh and many Anglo-Americans feared that immigrants from Russia and Eastern Europe would bring socialist ideas and revolution to America. 

Indeed, the rise of American Socialism (spearheaded by Eugene Debs, among others) along with the increasing power of labor unions, led to an increasingly hostile backlash against liberal politics and immigrants from southern and eastern Europe. In 1917, 1921 and 1924, Congress passed a series of Immigration Exclusion Acts that explicitly limited migration from Southern and Eastern Europe, as well as from Asia.

The effect on American culture was profound, in that nativist sentiment ran high, suspicion of those who spoke foreign languages was common, and many Americans who did not live in big cities came to fear popular cultural movements such as Jazz, night life and even the radio, which many preachers railed against as a conduit for spreading propaganda and immoral attitudes. All of these sentiments were reinforced by the isolationist politics that resulted from World War One, and which produced the conservative, so-called “do-nothing presidencies” of Harding and Coolidge, whose main qualifications were their patrician, good-old-boy credentials.