Heading into the 2009 Major League Baseball draft, Baseball America rated Barnhart as the best available player from Indiana.
Due to his commitment to Georgia Tech, he fell to the 10th round, when he was chosen by the Cincinnati Reds with the 299th overall selection.
Barnhart opted to sign with the Reds, rather than enroll at Georgia Tech.

In 2010, Barnhart played for the Billings Mustangs of the Rookie-level Pioneer League.
In 2011, he played for the Dayton Dragons of the Class A Midwest League.
He spent the 2012 season with the Bakersfield Blaze of the Class A-Advanced California League and Pensacola Blue Wahoos of the Class AA Southern League.
He played for Pensacola in 2013, and was named a Southern League All-Star.

The Reds added Barnhart to their 40-man roster on November 20, 2013.
With Devin Mesoraco beginning the 2014 season on the disabled list, Barnhart made the Reds' 2014 Opening Day roster, as a backup to Brayan Peña.
Barnhart made his major league debut on April 3 against the St. Louis Cardinals.
Starting at catcher (with Homer Bailey the starting pitcher) and batting eighth, he went 0-for-4 with one strikeout.
Two days later, he got his first big-league hit, a single off New York Mets pitcher Dillon Gee; for the game, Barnhart went 2-for-4.

Barnhart was optioned to the Louisville Bats of the Class AAA International League on April 7, when Mesoraco was activated.
He was later recalled by the Reds, and on May 1, he hit his first major league home run, a fifth-inning solo shot off the Milwaukee Brewers' Marco Estrada.
He was optioned back to Louisville on May 18.
On July 6, with Peña on the paternity list and also forced to play more at first base due to injuries, the Reds recalled Barnhart.
Barnhart was optioned back to Louisville on July 11.

Due to injuries to Mesoraco, Barnhart started 67 games at catcher for the Reds in 2015 and 108 games in 2016.
On September 22, 2017, Barnhart signed a four-year contract extension with the Reds, worth $16 million, plus a $7.5 million club option for the 2022 season.
He led National League catchers in wins above replacement and caught stealing percentage.
He also led the major leagues in runner caught stealing (32).
After the 2017 season, he won the Rawlings Gold Glove Award.

In June 2019, he suffered a moderate abdominal and oblique strain, and was placed on the injured list.
In late August 2019, he gave up switch hitting and became a left-handed hitter.
Heading into the 2009 Major League Baseball draft, Baseball America rated Barnhart as the best available player from Indiana. Due to his commitment to Georgia Tech, he fell to the 10th round, when he was chosen by the Cincinnati Reds with the 299th overall selection. Barnhart opted to sign with the Reds, rather than enroll at Georgia Tech.
In 2010, Barnhart played for the Billings Mustangs of the Rookie-level Pioneer League. In 2011, he played for the Dayton Dragons of the Class A Midwest League. He spent the 2012 season with the Bakersfield Blaze of the Class A-Advanced California League and Pensacola Blue Wahoos of the Class AA Southern League. He played for Pensacola in 2013, and was named a Southern League All-Star.
The Reds added Barnhart to their 40-man roster on November 20, 2013. With Devin Mesoraco beginning the 2014 season on the disabled list, Barnhart made the Reds' 2014 Opening Day roster, as a backup to Brayan Peña. Barnhart made his major league debut on April 3 against the St. Louis Cardinals. Starting at catcher (with Homer Bailey the starting pitcher) and batting eighth, he went 0-for-4 with one strikeout. Two days later, he got his first big-league hit, a single off New York Mets pitcher Dillon Gee; for the game, Barnhart went 2-for-4.
Barnhart was optioned to the Louisville Bats of the Class AAA International League on April 7, when Mesoraco was activated. He was later recalled by the Reds, and on May 1, he hit his first major league home run, a fifth-inning solo shot off the Milwaukee Brewers' Marco Estrada. He was optioned back to Louisville on May 18. On July 6, with Peña on the paternity list and also forced to play more at first base due to injuries, the Reds recalled Barnhart. Barnhart was optioned back to Louisville on July 11.
Due to injuries to Mesoraco, Barnhart started 67 games at catcher for the Reds in 2015 and 108 games in 2016. On September 22, 2017, Barnhart signed a four-year contract extension with the Reds, worth $16 million, plus a $7.5 million club option for the 2022 season. He led National League catchers in wins above replacement and caught stealing percentage. He also led the major leagues in runner caught stealing (32). After the 2017 season, he won the Rawlings Gold Glove Award.
In June 2019, he suffered a moderate abdominal and oblique strain, and was placed on the injured list. In late August 2019, he gave up switch hitting and became a left-handed hitter.
Tucker Barnhart