2017–18 Boston Celtics season
The 2017–18 Boston Celtics season was the 72nd season of the franchise in the National Basketball Association. The Celtics originally acquired the number one pick of the NBA draft due to a previous trade involving the Brooklyn Nets, only to then trade it to the Philadelphia 76ers in exchange for two different draft picks. One of the picks would allow Boston to draft forward Jayson Tatum. Later, they acquired Gordon Hayward in free agency on July 7, 2017. They would also acquire Kyrie Irving from the Cleveland Cavaliers via trade on August 22, 2017 in exchange for Ante Žižić, Jae Crowder, All-Star point guard Isaiah Thomas, the Brooklyn Nets' unprotected first round pick in the 2018 NBA draft, and a 2020 second round pick, originally from the Miami Heat. The Celtics played the first game of the regular season on October 17, 2017, against the Cleveland Cavaliers.
The team retired the number 34 in honor of former small forward Paul Pierce on February 11, 2018, during a game against the Cavaliers, which ultimately didn't involve a conflict with both Isaiah Thomas and Jae Crowder returning that night, as they were traded to the Los Angeles Lakers and Utah Jazz respectively during the NBA trade deadline. Neither Thomas nor Crowder would return to Boston during this season, as the Lakers and Jazz already played against the Celtics in Boston before the trade deadline.
In the playoffs, the Celtics defeated the 7th seeded Milwaukee Bucks in the First Round in seven games, advancing to the Semifinals, where they faced the Philadelphia 76ers, winning in five games, advancing to the Conference Finals, where they faced the Cleveland Cavaliers in a rematch of last season's Eastern Conference Finals, in which the Cavaliers won 4–3. Despite losing both star acquisitions Gordon Hayward and Kyrie Irving before the playoffs began to season-ending injuries, the Celtics would make this series more hard-fought this time, but lost in seven games to the Cavaliers, losing 79–87 at home in Game 7. It marks the first time since the 1987–88 season that the Celtics made two consecutive Conference Finals.
Draft picks
| Round | Pick | Player | Position | Nationality | College |
| 1 | 3 | Jayson Tatum | SF | United States | Duke |
| 2 | 37 | Semi Ojeleye | PF | United States | Southern Methodist |
| 2 | 53 | Kadeem Allen | PG | United States | Arizona |
| 2 | 56 | Jabari Bird | SG | United States | California |
Despite having the best record in the Eastern Conference the previous season, the Celtics would originally win the number one pick at the end of the year because they activated the right to swap their own first-round draft pick with the Brooklyn Nets, who held the worst record of the entire NBA that same season. However, on June 19, four days before the 2017 NBA draft commenced, the Celtics would trade that coveted pick to the Philadelphia 76ers in exchange for the third pick of the draft and either the Sacramento Kings or Philadelphia 76ers' 2019 first round pick, depending on what happens in that year's draft. Other than that, the Celtics also hold three second round draft picks, each of which were acquired by trades, while losing their own second round pick as an added piece of help for the Nets later on down the line. Their first second round pick was acquired from the Phoenix Suns back when it was considered a first round pick from the Minnesota Timberwolves in exchange for Brandan Wright. The next second round pick was had from the Cleveland Cavaliers alongside their 2016 second round pick and Keith Bogans in exchange for John Lucas III, Erik Murphy, Dwight Powell, Malcolm Thomas, and the protected rights of the Sacramento Kings' own second round picks from both 2015 and 2017. Finally, their last second round pick was acquired from the Los Angeles Clippers in a three-way trade with the Phoenix Suns, where Boston would acquire Shavlik Randolph again and a trade exception from the Suns, as well as both Chris Douglas-Roberts and a second round pick from the Clippers.
With their top pick, the Boston Celtics selected a 19-year-old freshman, small forward Jayson Tatum, of Duke University. In his only season at Duke, Jayson averaged 16.8 points, 7.3 rebounds, 2.1 assists, 1.3 steals, and 1.1 blocks per game in over 29 games there, while also earning All-ACC Freshman Team and All-ACC Third Team honors throughout last season. Tatum would end the season as a near-unanimous NBA All-Rookie First Team member. In terms of their second round picks, the first one they took would be another small forward, this time being Semi Ojeleye, a transfer junior from Southern Methodist University. During his only year at Southern Methodist, Ojeleye helped lead the Mustangs to their second ever AAC Tournament victory by recording averages of 18.9 points and 6.8 rebounds per game there. As a result of his efforts, he became the AAC Tournament's MVP that year, as well as be named to the All-AAC First Team, the AAC Player of The Year, and was an honorable mention via the Associated Press for the NCAA All-American Team. For the second of Boston's three second round picks, at number 53, the Celtics selected senior shooting guard Kadeem Allen from University of Arizona. In his senior year at Arizona, he averaged 9.8 points and 4 rebounds per game, which would be enough for him to be named a member of the Pac-12 Second Team and Pac-12 Defensive Team. Finally, with their last second round pick at number 56, Boston chose another senior shooting guard, this time being Jabari Bird from the University of California. During his last season at California, Bird averaged 14.3 points and 4.3 rebounds for the Golden Bears, but he suffered a concussion during one of his last games there. Both Kadeem Allen and Jabari Bird would become the team's first ever players to sign two-way contracts with the team, meaning they get to split their playing time for at least this season between the Celtics and their NBA G League affiliate, the Maine Red Claws, with Maine holding them for the majority of this season as a result of the two-way contract's stipulations.