Although the denomination is often considered mainline, varying theological and missional emphases may be found among its congregations, including modernist, charismatic and conservative evangelical orientations.

Having a congregational polity, early Baptist churches in America operated independently from one another, following an array of Protestant theological paths, but were often unified in their mission to evangelize.

In the 18th century, they sometimes created local congregational associations for support, fellowship, and work (such as the founding of Brown University in 1764).

The evangelical mission led to the establishment of the national Triennial Convention in 1814, a collaborative effort by local churches to organize, fund, and deploy missionaries.

[9] Charles Evans Hughes, then Governor of New York and later Chief Justice of the United States, served the body as its first president.

"[10] These had contributed to establishing many schools for freedmen in the South after the American Civil War, as well as working on issues of health and welfare.

[10]As in many cases, the rhetoric of the annual conventions was sometimes ahead of local activity, but the denomination gradually made progress.

The following year, Dr. Thomas Kilgore Jr., pastor of the Second Baptist Church of Los Angeles, was elected the first black president of the convention.

[13] Rather than relying on decision-making at the annual convention by whichever churches happened to send delegates, the SCODS restructuring resulted in the following: A General Board was composed of duly elected representatives from geographically designated districts.

Local churches are organized into 33 regions; the ABCUSA General Board makes policy for the denomination's national agencies.

[17] The ABCUSA consists of 33 regional associations and conventions: The majority of the denomination's congregations are concentrated in the Midwest and Northeast United States.

Since the beginning of the 21st century, membership began to decline and stagnate again, with the ABCUSA reporting 1,145,647 members in 5,057 churches at the end of 2017.

[24][25] American Baptists believe that the Bible is the inspired word of God and the final authority in matters of faith.

[28] In 1992, the ABCUSA General Board adopted a resolution that stated, "We affirm that the practice of homosexuality is incompatible with Christian teaching."

[29][30] So far, at least seven regions in the ABCUSA (Evergreen, Wisconsin, Rochester-Genesee, Metro Chicago, Metropolitan New York, Massachusetts, and Philadelphia) support full inclusion of homosexuals into Baptist life.

[36] The ABCUSA has consistently allowed each congregation to determine whether or not to perform same-sex marriages, or ordain LGBT clergy.

[37] The ABCUSA General Board voted in 2005 to amend the declaration We are American Baptists to define marriage as "between one man and one woman" and maintain that "the practice of homosexuality is incompatible with Biblical teaching.

Among its universities and colleges, some are also dually-affiliated with the National Baptists—a predominantly African American or Black Baptist denomination founded by freedmen and slaves.