Paul Sterling DeJong (born August 2, 1993) is an American professional baseball infielder for the St. Louis Cardinals of Major League Baseball (MLB). He made his major league debut on May 28, 2017, and spent most of his first season playing shortstop, and also played second base. A right-handed batter and thrower, DeJong stands 6 feet 1 inch (1.85 m) tall and weighs 195 pounds (88 kg).
A native of Orlando, Florida, the Cardinals selected DeJong in the fourth round of the 2015 MLB draft after he attended and played college baseball at Illinois State University (ISU). In 2017, he led National League (NL) shortstops in home runs with 25.
DeJong graduated from Antioch Community High School in Antioch, Illinois, in 2011.  He then attended Illinois State University (ISU) where he played college baseball for the Redbirds. As a freshman in 2013, he batted.260 in 100 at bats with no home runs. After increasing his dedication to weight training between his freshman and sophomore years, DeJong noted, he gained approximately 20 pounds (9.1 kg) of muscle mass, and in strength and speed, thus improving his play on the field. In 2014, he played second base, third base, and catcher, batting .349, nine homers, and 48 runs batted in (RBI). After the 2014 season, the Pittsburgh Pirates chose DeJong in the 38th round of the Major League Baseball (MLB) draft as a catcher. He did not sign with the Pirates and instead returned to Illinois State.  
In 2015, DeJong batted .333 while leading the Redbirds in hits (70), runs scored (47), doubles, home runs (14), and RBI (48). He played four positions including shortstop, second base, third base, and catcher, and also appeared at designated hitter. He was named All- Missouri Valley Conference first team as a utility player. He also earned Academic All-District honors for District 5. 
A graduate of ISU in 2015 with a degree in biochemistry with a pre-medical emphasis, DeJong still had one year of college baseball eligibility remaining. Baseball America ranked him as the 108th-best prospect for the 2015 MLB draft.  The St. Louis Cardinals selected him in the fourth round.    The Cardinals were intrigued not only by DeJong's baseball talents, but also by his preparation in academics, having graduated with a 3.74 GPA and a plan to attend medical school in case a career in professional baseball would not have worked out. 
DeJong signed with the Cardinals for $200,000, and made his professional debut with the Johnson City Cardinals of the Rookie-level Appalachian League. After 10 games, he was promoted to the Peoria Chiefs of the Class A Midwest League.  Between the two teams, he batted .316/.394/.516.  In 2016, he played for the Springfield Cardinals of the Class AA Texas League, and was selected as a Texas League All-Star.  He finished the 2016 season batting .260 with 22 home runs and 73 RBIs.  After the season, the Cardinals assigned DeJong to the Glendale Desert Dogs of the Arizona Fall League (AFL). 
The Cardinals assigned DeJong with the Memphis Redbirds of the Class AAA Pacific Coast League (PCL) to begin the 2017 season. In 46 games, he was batting .294 with 11 home runs and 31 RBI, and had played 37 games at shortstop, four at second base and three at third base, prior to his first major league promotion. The Cardinals promoted DeJong to the major leagues on May 28, 2017, when they placed second baseman Kolten Wong on the disabled list (DL). 
DeJong made his major league debut on May 28, 2017, at Coors Field versus the Colorado Rockies. He faced Greg Holland in his first at bat, and hit a home run on his first swing, becoming the ninth Cardinals player to homer in his first at bat in the major leagues.  On July 8 versus the New York Mets, he set both a Cardinals shortstop and a number eight hitter record with four extra base hits in one game, including three doubles and one home run.  The next day, DeJong set a rookie record for extra-base hits in a three-game series with seven.  After batting .298/.347/.638 (.985 OPS) with eight home runs and 16 RBI in the month of July, DeJong was named the National League (NL) Rookie of the Month. He was the first Cardinals' player to win the award since Wong in May 2014. 
On August 19, DeJong hit his 20th home run, versus Juan Nicasio, becoming just the fourth Cardinals rookie to do so, in a 6−4 loss to the Pittsburgh Pirates.  DeJong finished his 2017 rookie campaign with a .285 batting average, 25 home runs, and 65 RBI, leading NL shortstops in home runs.  Only Albert Pujols had hit more home runs as a rookie in club history, doing so in 2001. DeJong's combined output between Memphis and St. Louis in 2017 included 38 home runs.  He placed second in the 2017 NL Rookie of the Year balloting to Cody Bellinger, who won unanimously. 
DeJong signed a six-year contract extension finalized on March 5, 2018, worth a guaranteed total of $26 million, through the 2023 season. The deal also includes two option years and a total possible value of $51.5 million, confirmed a source. The deal is one of the largest ever given to a player who has not had a full year of service. 
After the 2017 season, DeJong participated in a scientific study as laboratory assistant with Dr. Lawrence Rocks exploring the effects of differing temperatures on the flight of the path of the baseball.  DeJong and Dr. Rocks also appeared together on MLB Now at the 2017 winter meetings.  
- List of Illinois State University alumni
- List of Major League Baseball players with a home run in their first major league at bat
- List of people from Orlando, Florida