As a sophomore in 2015, Senzel batted .325 with a .495 SLG, 4 home runs, and 28 RBIs.[10] In the summer of 2015, he played for the Brewster Whitecaps of the Cape Cod Baseball League (CCBL), and received the league's MVP and Outstanding Pro Prospect awards after hitting .364 with four home runs and 33 RBIs. He was inducted into the CCBL Hall of Fame in 2024.[11][12][13][14]
Senzel was considered to be one of the best available players in the 2016 Major League Baseball draft,[17] The Philadelphia Phillies, who had the first overall pick, scouted Senzel.[18] Many baseball executives and scouts agreed that Senzel was the safest pick in the draft.[18] He was also rated as the best hitter in the draft because of his abilities to hit gap-to-gap with power.[19]
Senzel began 2018 with the Louisville Bats of the Triple–AInternational League. On June 23, 2018, it was revealed that Senzel's 2018 season ended after he required surgery to repair a torn ligament on his right index finger.[30] Upon his return from injury, Senzel told new Reds' manager David Bell, that he was preparing to play center field.[31]
The Reds allowed Senzel to play center field in Spring Training with a chance to compete with Scott Schebler for the starting role.[32] He had a .308 with a .300 on-base percentage and a .462 slugging percentage.[33] Despite his performance, the Reds elected to send Senzel to minor league camp.[34] Senzel's agent assumed that the service-time rules in baseball was the majority influence on the team's decision; if Senzel were to play 12 days in the minors before being promoted to the majors, the Reds would receive another year of club control.[35] Just three days later, Senzel sprained his ankle during a minor league game.[36] In eight games with Louisville, Senzel hit one home run and batted .257.[37]
On May 3, 2019, Senzel was called up to the majors by the Reds.[38][39] He made his major league debut that day at Great American Ballpark, going 1-for-5 with two strikeouts and two walks.[40] Senzel's first hit was a slow-roller to third that he beat out off the San Francisco Giants' Tony Watson.[41] Senzel hit his first major league home run on May 4, off Giants' Dereck Rodríguez.[42] His second and third home runs came two days later at home against the Giants off Drew Pomeranz.[43] Senzel finished the month of May with a .279 batting average, four home runs, 12 RBIs, and 12 walks.
On September 12, 2019, Senzel was placed on the injured list with a torn labrum.[44] In 104 games of his first season in the Majors, Senzel batted .256 with 12 home runs, 20 doubles, and 42 RBIs.
In the following season, Senzel returned to the injured list on August 19 and missed 27 games in August and September for undisclosed reasons.[45][46] During the pandemic-shortened season, Senzel batted .186/.247/.357 with two home runs and eight RBIs in 23 games.
On June 13, 2021, Senzel was placed on the 60-day injured list with left knee inflammation.[47] On August 15, Senzel was activated from the injured list and optioned to Triple-A Louisville, but days later was returned to the injured list when it was discovered that Senzel's knee was not healthy enough for him to play.[48] He was non-tendered and became a free agent on November 17, 2023.[49]
On December 12, 2023, Senzel signed a one-year contract with the Washington Nationals.[50] On March 28, 2024, Senzel suffered a broken right thumb while fielding ground balls during pregame. He was scratched from the Nationals' Opening Day lineup before playing in his first game with the club.[51] In 64 games for Washington, he batted .209/.303/.359 with seven home runs and 18 RBI. Senzel was designated for assignment by the Nationals on July 5.[52] He was released by the organization on July 11.[53]
On July 17, 2024, Senzel signed a major league contract with the Chicago White Sox.[54] In 10 games for Chicago, he went 3–for–30 (.100). Senzel was designated for assignment by the White Sox on August 26.[55] He elected free agency on August 28.[56]
Senzel is married to Emily. The couple got engaged on January 9, 2021.[57] Their first child, Nicholas Peter was born on November 29, 2021.[58] Their second child, Molly Blake was born on February 2, 2024.[59]