DiBartolomeo averaged 17.8 points per game during his four-year college basketball career at the NCAA Division 3 program Rochester, scoring 1,779 career points, which ranked him third in the school's history. His 533 career assists and 201 career steals were second on Rochester's all-time list. He concluded his college career as the 2013 D3hoops.com and 2013 DIII News Player of the Year, while earning spots on the NABC, D3hoops.com, DIII News, USBWA All-America First Teams. He also garnered Rochester's Louis Alexander Alumni Award and was named Paychex Local Male College Athlete of the Year, which was presented by the Rochester Press Radio Club. Reflecting on DiBartolomeo's college career, Rochester head coach, Luke Flockerzi, stated in October 2015: "John was truly a special player for us at Rochester. He is simply the hardest-working and most-dedicated player I’ve ever coached. His humility drives him, and has created a work ethic that is unmatched."
In August 2013, DiBartolomeo signed a three-year deal with the Spanish club CAI Zaragoza. He was later loaned by Zaragoza to Palma Air Europa of the LEB Plata, for the 2013–14 season. In 33 games played with Palma, in the 2013–14 season, he averaged 15.1 points, 3.6 rebounds, 4.7 assists, and 1.5 steals per game. He returned to Palma for the 2014–15 season, after helping the club earn a league promotion to the LEB Oro. In 28 games played with Palma, in the 2014–15 season, he averaged 11.3 points, 4.1 rebounds, 2.3 assists, and 1.6 steals per game.
On June 17, 2015, DiBartolomeo signed a two-year deal with the Israeli team Maccabi Haifa. after his contract with Zaragoza, who still owned his rights, was bought out. On February 6, 2016, DiBartolomeo recorded a season-high 22 points in a 91-56 win over Israeli powerhouse Maccabi Tel Aviv. DiBartolomeo, who made 5/7 shots from 3-point territory, was elected co-MVP of the game, alongside his teammate Gregory Vargas. On December 25, 2016, DiBartolomeo recorded a career-high 35 points, shooting 11-of-14 from the field, along with 7 rebounds and 5 steals in a 93–85 win over Hapoel Eilat. He was subsequently named Israeli League Round 11 MVP. In 2016-17, he averaged 11.0 points, 3.9 rebounds and 3.0 assists a game in regular season, before stepping up in the playoffs, where he tallied 19.2 points, 3.5 boards and 3.0 assists per contest, steering Maccabi Haifa to the championship game. Despite falling short to Hapoel Jerusalem in the title game, DiBartolomeo was named Israeli League MVP for the 2016-17 season.
On October 22, 2018, DiBartolomeo recorded a season-high 22 points, shooting 6-of-13 from the field, along with seven rebounds and two assists in a 66–64 win over Hapoel Be'er Sheva. On November 1, 2018, DiBartolomeo was named Israeli League Player of the Month after averaging 17.3 points, 4.8 rebounds, 2.8 assists and 1.5 steals in four games played in October. On June 13, 2019, DiBartolomeo led Maccabi to their 53rd Israeli League title after defeating Maccabi Rishon LeZion 89–75 in the final. He scored 15 points by playing 18 minutes off the bench and was named the Final Four MVP.
2019–20 season
On November 7, 2019, DiBartolomeo recorded a EuroLeague career-high 19 points, shooting 6-of-8 from the field, along with three steals in a 104–78 win over Alba Berlin. On December 5, 2019, DiBartolomeo was ruled out for six months after he suffered from a pectoral muscle tear in a game against Bayern Munich. He suffered a season-ending Achilles injury on June 9, 2020. The injury was less severe than initially expected as there was no tear, and he is expected to be back for the next season.
DiBartolomeo is a member of the senior Israel national basketball team. On September 6, 2018, he made his first appearance for the Israeli team in a 91–73 win over Russia, recording 12 points off the bench.
