Tarczewski attended Stevens High School in Claremont, New Hampshire for two years, leading Stevens High School's varsity basketball team to the NHIAA Final Four in 2008–2009. Tarczewski transferred to St. Mark's School in Southborough, Massachusetts after that season. Ranked as the No. 4 overall prospect in the country and the No. 3 center with a scout grade of 97 by ESPN in the class of 2012, Tarczewski led St. Mark's to a 28–2 record as a senior for coach Dave Lubick. He was named MVP of the Independent School League. Tarczewski averaged 17.0 points and 12 rebounds per game as a junior, and averaged 20.7 points, 10.2 rebounds and 2.7 blocks per game while shooting 63 percent from the floor as a senior. He tallied 14 points (6-of-8 FGs) and 10 rebounds in the Jordan Brand Classic, April 14 in Charlotte, North Carolina. He saw eight minutes of action in the 2012 Nike Hoop Summit, April 7 in Portland, Oregon. Among his other honors, Tarczewski helped the Lions to four consecutive NEPSAC championship games, including a victory in the 2012 Class AA title game, and was a first-team all-NEPSAC Class AA selection as a junior and senior. He participated in the Adidas Nations top-50 camp, the Adidas Super 64, the Double Pump Best of the Summer event and the Peach Jam tournament prior to his senior season.[4]
Tarczewski played four seasons with Arizona, helping the Wildcats to reach 110 victories, tying the school record. In his senior season, he averaged 9.4 points, 9.3 rebounds and 1.4 blocks and was named to the Pac-12 All-Conference Second Team and the Pac-12 All-Defensive Team.[4][5]
On March 14, 2017, Tarczewski signed with Olimpia Milano for the remainder of the season.[12] He posted 6.7 points and 5.1 rebounds per game. On June 30, 2018, he inked a two-year contract extension.[13] During the 2019–20 season, he averaged 8.1 points and 5.8 rebounds per game. Tarczewski signed a three-year contract extension in May 2020.[14] On July 2, 2022, Tarczewski officially parted ways with the Italian club after five years, having won seven domestic titles and reached the EuroLeague Final Four once (2021) during his stint.
On July 12, 2022, Tarczewski signed with Gunma Crane Thunders of the Japanese B.League.[15][16] On June 19, 2023, he re-signed with Gunma Crane Thunders.[17] On June 13, 2024, he re-signed with Gunma Crane Thunders.[18]