Happ is the all-time leading rebounder for the Wisconsin Badgers, where he started all 139 games of his college career and is the school record holder in double-doubles and triple-doubles. Happ is one of just six players in NCAA history to record at least 2,000 points, 1,000 rebounds and 400 assists.[3]
Happ started every game in 2015–16 for the Badgers and was named Big Ten Freshman of the Year.[5] He was also a unanimous selection the Big Ten All-Freshman Team and named to the Big Ten All-Defensive Team. He was selected to the third team All-Big Ten by the media and honorable mention by the coaches. As a sophomore, Happ became a greatly improved player.[6] He was named a third-team All-American after averaging 14 points per game.[7]
Despite not being listed in most mock drafts, Happ declared for the 2018 NBA draft without hiring an agent, giving him the option to return to college, which he later did.[8][9]
On December 22, 2018, Happ grabbed his 1,000th career rebound in a win over Grambling State.[10] On February 12, 2019, he scored his 2000th point, making him the first player in the Big Ten to score 2,000 points and collect 1,000 rebounds in 35 years.[11] As a senior, Happ averaged 17.9 points, 10.3 rebounds, 4.6 assists, 1.0 steals and 1.2 blocks per game.[12] Happ was the only player in NCAA during the 2018–19 season, to lead their respective team in all 5 statistical categories.
On July 18, 2019, Happ signed a two-year deal with the Greek EuroLeague club Olympiacos, of Piraeus, Greece, to play under head coach David Blatt.[14]
Vanoli Cremona (2019–2020)
After appearing in only one game with Olympiacos, Happ was loaned on November 5, 2019, to the Italian League club Vanoli Cremona, for the remainder of the 2019–20 season.[15] On June 30, 2020, the Greek club officially announced that they had forfeited their contract option and Happ thus became a free agent. Happ averaged 18.3 points per game, 9.3 rebounds per game and 2.5 assists per game with Cremona.[16]
Fortitudo Bologna (2020–2021)
Happ signed with Fortitudo Bologna of the Lega Basket Serie A on July 10, 2020.[17] After suffering a left elbow injury, he was ruled out for three to four weeks on October 25.[18]
On July 8, 2022, Happ signed with Río Breogán of the Spanish Liga ACB.[22] He played all 34 league games, averaging 12.6 ppg, 7.9 rpg and 17.3 PIR per game, helping the team to a 10th-place finish and securing a European spot.