[2] Early in 2016, Waardenburg played four games for the Super City Rangers in the New Zealand National Basketball League.
In July, he competed in the Adidas Nations Tournament in Los Angeles, where he was ranked in the top 10 players of the camp.
[4] In August 2016, Waardenburg joined the New Zealand Breakers of the Australian National Basketball League (NBL) as a development player, signing a non-paid contract to maintain his amateur status.
[4] In October, he won tournament MVP honours when he helped Rangitoto win the SAS Secondary Schools National Championship, tallying 18 points, eight rebounds and four blocks in the final game.
[2][6] Waardenburg joined the Miami Hurricanes of the NCAA Division I in January 2017[4] for the second semester of the 2016–17 season, but did not compete and redshirted.
[2] In October 2020, Waardenburg sustained a left foot injury in practice and was subsequently ruled out for the entire 2020–21 season.
[16] He was named the recipient of the NBL Next Generation Award for the 2022–23 season after averaging 10.8 points, shooting at 53.6 per cent from the field to go with 5.0 rebounds and 1.2 assists in 25 games.
[17] Following the NBL season, he moved to Germany to play for Riesen Ludwigsburg,[18] where he averaged 5.4 points and 2.4 rebounds in 20 games to finish the 2022–23 Basketball Bundesliga.
[19] After a minor stint with the Minnesota Timberwolves during the 2023 NBA Summer League,[14] Waardenburg re-joined the Taipans for the 2023–24 NBL season.