Junior On April 6, 2013, Bastian was selected by the
Mississauga Steelheads of the
Ontario Hockey League (OHL) in the seventh round, 127th overall, in the 2013
OHL priority selection. Bastian played at the
midget level with the
Brantford 99ers of the
Greater Ontario Junior Hockey League to begin the 2013–14 season, collecting 11
goals and 16
assists for 27
points through 29 games. He then joined the Steelheads later that season, contributing two goals and one assist in 21 games. During the
2014–15 season, his first full campaign, he was the only Steelhead to play in all 68 games, while tallying 17 goals and 29 assists, earning him the honor of being Mississauga's Hardest Working Player. During the
2015–16 season, Bastian played on the Steelheads' top line, registering four goals and an assist through his first six games. On September 25, 2015, Bastian recorded two goals and an assist in a 7–0 victory over the
Ottawa 67's. On December 6, Bastian scored the first goal in the Steelheads' teddy bear toss night, while also registering two assists in the game. On January 7, 2016, he was named to Team Orr to participate in the 2016
CHL/NHL Top Prospects game. At the game on January 28, he helped Team Orr to victory over Team Cherry. On February 15, he recorded two goals as part of a 6–2 victory over the
Niagara IceDogs. He finished the season with 19 goals and 40 assists in 64 games. During the playoffs, he notched four assists through five games. After the season, the NHL Central Scouting Bureau ranked Bastian 35th overall among North American skaters in their Final Rankings before the
2016 NHL entry draft. On June 25, 2016, he was drafted by the
New Jersey Devils in the second round, 41st overall, of the draft. Bastian signed a three-year,
entry-level contract with the Devils on October 20, 2016. In 58 games during the
2016–17 season, he collected 16 goals and 29 assists. During the playoffs, on March 30, 2017, he recorded a
hat-trick in a 6–4 victory over the Ottawa 67's. He finished the playoffs with seven goals and seven assists in 20 games,
Professional New Jersey Devils After attending the New Jersey Devils' training camp, Bastian was assigned to their
American Hockey League affiliate, the
Binghamton Devils, on September 26, 2017, to start the
2017–18 season. In the season opener on October 7, he scored his first professional goal on a
penalty shot against
Christopher Gibson, helping the Devils to a 2–1 win over the
Bridgeport Islanders. On December 8, he scored two goals against the
Syracuse Crunch, the only Devils goals in a 5–2 loss. He finished the season managing 10 goals and eight assists through 68 games. On September 23, 2018, Bastian was assigned to Binghamton to start the
2018–19 season. Through his first 21 games of the season, he recorded six points. He made his NHL debut that night, getting into his first NHL fight against
Josh Manson and registering 9:32 of ice time in a 3–2 loss to the
Anaheim Ducks, but he was returned to the AHL soon after. On February 24, he was recalled to New Jersey again. The next day, he scored his first NHL goal as part of a 2–1 victory against the
Montreal Canadiens. On March 1, in a contest against the
Philadelphia Flyers, Bastian left the game in the third period with what was later determined to be an upper-body injury. On March 25, he returned to practicing with the team, On April 6, he recorded two goals as part of a 4–3
overtime win against the
Florida Panthers, finishing his time in the NHL with three goals through seven games. He was reassigned to Binghamton the next day, playing with the team until he ended the season with 18 goals and 24 points in 58 games. Bastian was assigned to Binghamton to start the
2019–20 season on September 27, 2019. Through his first 13 games, he managed two goals and seven assists to start the season. On February 19, 2020, he recorded a goal and an assist in a 5–3 win over the
Toronto Marlies. He ended the season with 22 assists and 38 points through 62 games. Before the
2020–21 season, Bastian was named to New Jersey's opening roster for the first time in his career. On February 3, 2021, after recording four points through the first nine games of the campaign, he was added to the Devils'
COVID-19 list, staying there until he was removed 12 days later. On March 18, in a 3–2 win over the
Pittsburgh Penguins, Bastian left the game in the second period. Two days later, it was announced that he would be week-to-week with a lower-body injury. He returned to the lineup in a 6–3 win over the New York Rangers on April 17 after missing 15 games. He finished the season with three goals and seven assists in 41 games, while leading the team in hits with 136. On June 15, Bastian was re-signed to a two-year, contract by the Devils.
Seattle Kraken, second stint with New Jersey, and Dallas Stars On July 21, 2021, Bastian was selected from the Devils at the
2021 NHL expansion draft by the
Seattle Kraken. He was named to the team's opening roster for their inaugural
2021–22 season. He scored his first goal with the team in a 5–4 loss to the
Arizona Coyotes on November 6. He played 12 games with the Kraken and added an assist before he was placed on
waivers on November 24. He was claimed off waivers the next day by his former team, the New Jersey Devils. After registering five points in 17 games with the Devils, he was placed on the team's COVID-19 list on January 8. After missing one game, he was taken off the list on January 13, On April 3, he left the first period of a 4–3 loss to the Islanders with an undisclosed injury. He missed three games due to the injury, but tallied two assists in three games after returning. He finished the season notching 11 goals and five assists in 60 games with the Devils. On November 26, 2022, in a game against the
Washington Capitals, Bastian suffered an injury to his shoulder. He was placed on
injured reserve retroactive to that date on December 22, after missing 11 games. On January 19, 2023, he was removed from the injured reserve list and played his first game back against the Seattle Kraken. After trying to play through his injury, he again aggravated it, missing 11 games from March 12 to April 4. He ended the season with six goals and nine assists through 43 games. Through 12 playoff games, he finished with only that goal and an assist. On February 22, 2024, in a contest against the
New York Rangers, Bastian left the game with a lower-body injury. The following day, he was placed on injured reserve by the Devils. After missing the final 26 games of the season, Bastian ended the campaign with five goals and seven assists in 54 games. During the
2024–25 season, after a fight with
Ryan Lomberg in a game against the
Calgary Flames on November 1, 2024, Bastian left with a jaw injury. He was placed on long-term injured reserve retroactive to that date on November 18, and after missing 16 games, he was taken off of injured reserve on December 10. He ended the season with four goals and six assists through 59 games. On August 9, 2025, as a
free agent, Bastian signed a one-year, contract with the
Dallas Stars. ==Career statistics==