Following a strong start to the 2022 season, Riley signed a franchise-record ten-year contract extension worth $212 million.

[1][2][3] Riley attended DeSoto Central High School in Southaven, Mississippi, where he played baseball as a shortstop and pitcher.

[4][5] Riley played American football as a quarterback during his freshman and sophomore years in high school.

[6] Riley was committed to play for the Mississippi State Bulldogs baseball team until he was drafted by the Atlanta Braves in 2015.

[9][10] Though he was committed to Mississippi State Bulldogs baseball team,[11][12] Riley chose to sign with the Braves for $1.6 million.

[19][20] In 129 games between Florida and Mississippi, Riley hit .275/.339/.446 with 20 home runs and 74 RBIs, while on defense he committed 20 errors at third base.

[27][28] He made his major league debut that night and, in his second at bat, hit a home run off Michael Wacha.

At the time, his seven home runs in fourteen games were the second most to begin a career, trailing only Trevor Story (Aristides Aquino has since passed them both with nine).

On June 1, he hit his eighth home run in 16 games, becoming the fourth player in major league baseball history to achieve this feat.

[38] He finished the 2021 season hitting .303 with 33 home runs (10th in the NL), 107 RBIs (2nd), 168 strikeouts (4th), and a .898 OPS, joining Eddie Mathews and Chipper Jones as the only Atlanta third basemen to hit .300 with at least 30 home runs and 100 RBIs in a season at the age of 24 or younger.

Ozzie Albies put up similar numbers, and the pair became the fifth set of teammates to individually construct 30-home run, 100-RBI seasons at the age of 24 or younger.

[36] On October 16, 2021, Riley recorded his first career walk-off hit in Game 1 of the NLCS against the Los Angeles Dodgers, allowing Ozzie Albies to score and the Braves to win 3–2.

After the season ended, Riley and three teammates (Freddie Freeman, Max Fried, and Ozzie Albies) won the Silver Slugger Awards for their respective positions.

[48][49] On August 1, the Braves announced that Riley had been signed to a ten-year contract extension, worth $212 million.

[50] The contract is the largest in team history,[51] exceeding the length and total value of an extension signed by teammate Matt Olson before the 2022 season began.