The county is named for Henry Wharton Conway, a politician from a powerful political family who served as the delegate from the Arkansas Territory to the U.S. Congress from 1823 to 1827.

In 2010, the center of population of Arkansas was located in Conway County, near the city of Plumerville.

When the Little Rock and Fort Smith Railroad planned built tracks 1 mile (1.6 km) north of Lewisburg in 1871, the proposed depot was to be named Morrilton after farmer E. J. Morrill, who sold the land to the railroad.

The northern 16 square kilometres (1,600 hectares) of Conway County is protected within the Ozark National Forest, a small part of a large protected forest spanning parts of 16 Arkansas counties.

Conway County is home to five Wildlife Management Areas (WMAs) under Arkansas Game and Fish Commission jurisdiction.

As of the 2020 United States census, there were 20,715 people, 8,309 households, and 5,600 families residing in the county.

For the bulk of the 20th century, Conway County was reliably Democratic, voting solidly for the party in every presidential election except for the 1972 and 1984 landslides of Richard Nixon and Ronald Reagan, respectively.

Former Governor Bill Clinton won the county twice in his 1992 and 1996 victories while comfortably sweeping his native Arkansas.

In 2016, Republican Donald Trump won Conway County with 61% of the vote and a 28.6% margin of victory over former First Lady of Arkansas and the U.S. Hillary Clinton, owing both to Trump's strength in Rural America and the decline of the Clinton brand in their home state.

Trump would top his vote share and margin of victory in the county twice since then, winning with a 35.4% margin of victory and more than 65% of the vote over Democrat Joe Biden in 2020 (despite Biden winning nationwide), followed by a 40.3% margin of victory and 69% vote share as he reclaimed the Presidency in 2024, the latter of which stands as the best performance for a Republican presidential candidate in county history.

The Democratic Party continued to win all local county and city elected offices until 2018, when two members of the Republican Party were elected: Keith Long as Justice of the Peace and Dennis Decker as County Coroner.

In the 2022 midterm elections, the county government flipped red, with Republicans winning all but three contested seats.

Additionally, four Republicans were newly elected as new justices of the peace, the party flipped three Morrilton City Council seats – including Isaac Decker, who became the youngest to ever be elected, at age 20 – and the Oppelo Mayoral race.

Each township includes unincorporated areas; some may have incorporated cities or towns within part of their boundaries.

However, the United States census does list Arkansas population based on townships (sometimes referred to as "county subdivisions" or "minor civil divisions").

Each town or city is within one or more townships in an Arkansas county based on census maps and publications.