Sean O'Brien, president of the International Brotherhood of Teamsters, spoke Monday at the Republican National Convention.

O’Brien spoke at the Republican National Convention last month, in a move that frustrated many Democrats, though he did not endorse Republican presidential nominee Donald Trump.

Sean O'Brien, President of the International Brotherhood of Teamsters, speaks on the first day of the Republican National Convention, Monday, July 15, 2024, in Milwaukee.

Sean O'Brien, the colorful and combative leader of the International Brotherhood of Teamsters, is providing an unexpected ...

Sean O'Brien, president of the International Brotherhood of Teamsters, gave Monday's keynote speech at the Republican National Convention, delivering one of the most anti-big business speeches in ...

Sean O’Brien on Monday became the first Teamsters union president to speak at a Republican National Convention. In his speech, he said the American worker is being taken for granted. “The ...

GONYEA: In the spirit of working with both parties, Sean O'Brien has also asked to speak at the Democratic National Convention next month, but he says he's not yet heard back on that request.

In recent history, labor unions overwhelmingly back Democrats. President Biden calls himself the most pro-union president ever. But at the RNC, the head of the teamsters had a prime speaking slot.

SEAN O'BRIEN: President Trump had the backbone to open the doors to this Republican convention, and that's unprecedented.