The central organizational front for Democrats in the Senate, its primary function is communicating the party's message to all of its members under a single banner.

Since Oscar Underwood's election in 1920, the chair of the Senate Democratic Caucus has also concurrently served as the floor leader as part of an unwritten tradition.

[citation needed] In response, then-Democratic Leader Harry Reid created the position of vice-chair when Democrats formally took control in 2007.

The United States Senate Democratic Conference Secretary, also called the Caucus Secretary was previously considered the number-three position, behind the party's floor leader and the party's whip, until in 2006, when Democratic leader Harry Reid created the new position of Vice-Chairman of the caucus.

On December 8, 2022, Sen. Brian Schatz of Hawaii was elected to the newly created position of Deputy Caucus Secretary, assuming the office at the beginning of the 118th Congress on January 3, 2023.