As one of Hitler's earliest followers and friends, he held influential positions in the party during the Weimar Republic, but increasingly lost influence during the Nazi era.

As a teenager, he volunteered for service in World War I and fought on the front lines in the Royal Bavarian 19th Foot Artillery Regiment.

[2] In 1920 he met Hitler in the regional press office of the Reichswehr (Army of the Weimar Republic) and joined the renamed National Socialist German Workers' Party in March 1920.

[2] Esser was able to use his abilities as a public speaker to rouse his audience, encouraging them to attack the political meetings of groups and parties that the NSDAP frowned upon.

Esser's speeches were described by Louis Snyder as "crude, uncultured, of low moral character", featuring the kernel of future Nazi policies: extreme nationalism and anti-Semitism.

[4] At the time of the Beer Hall Putsch on 8–9 November 1923, Esser gave a speech and drafted the Party's "proclamation to the German people", but told Hitler that he was ill and did not participate in the actual march.

On 9 July 1924 he was elected the Deputy Chairman of the Nazi front organization, the Greater German People's Community based in Bavaria under Streicher.

He immediately made enemies with Gregor Strasser who was a leader of a rival organization in northern and western Germany which threatened to split the party in two.

[13] This was followed on 1 March 1934 by his appointment as Bavaria's Minister of Economics by Bavarian Reichsstatthalter (Reich Governor) Franz Ritter von Epp.

[1] Esser intrigued against the powerful Gauleiter of Gau Munich-Upper Bavaria Adolf Wagner and, as a result, was forced out of his ministerial posts on 14 March 1935.

[14] His last official duty was on 24 February 1945 in Munich, delivering a speech on behalf of Hitler at the 25th anniversary of the adoption of the Nazi Party program.

[2] Charged under the new West Germany anti-Nazification laws, he was found guilty of being a "major offender" and sentenced to five years hard labour with a loss of civil rights for life.