As a youth, Macallister played for his local Manly Warringah Dolphins before moving on to Sydney Olympic (then known as the Olympic Sharks). He marked his professional debut for the club in 1999 by scoring in his first appearance.
Having won the 2001–02 National Soccer League with the Sharks, Macallister proceeded to join another club from Sydney, the now defunct Northern Spirit. Macallister was then supposed to have left for Switzerland and FC Aarau in August, but immediately regretted signing the contract. The transfer was eventually called off and Macallister instead continued playing for Northern Spirit until he was bought by the Norwegian club Brann in February 2004.
After some initial success – he scored two goals against Molde in the second round of the 2004 season – Dylan figured mostly as a substitute. He scored 10 goals in 38 appearances which equates to approximately 20 matches in terms of playing time. Macallister's first season was blighted by a fatigue injury and after a good start to his second season he suffered a training injury, sidelining him for eight weeks.
Macallister was sold to Lyn on 29 March 2006 and debuted in the season opener against Start. He appeared in the starting line-up in his third and fourth matches, scoring a fine goal in the fourth, but failed to become a regular.
Following the end of the transfer dispute over John Obi Mikel and subsequent return of Lyn's other Nigerian players, Chinedu Ogbuke and Ezekiel Bala, Dylan Macallister was one of three non-EU players on the team at a time when Norwegian clubs were only allowed two non-EU players in their matchday squads. He was therefore loaned out to the First Division club Sparta Sarpsborg, from 16 August until the end of the season.
During his stay at Sparta he made nine appearances, scoring two goals. Sparta retained their spot in the league, but Macallister's season ended on a dull note as he was sent off in his last game. He returned to Lyn for the 2007 season, but made just five league appearances for the club, scoring no goals.
His contract with Lyn originally lasted to the end of the 2008 season, but it was announced on 28 March that he was released of his contract, and had signed with Australian A-League club Central Coast Mariners. He scored two goals on debut for the Mariners against the Queensland Roar.
On 13 May 2010, it was announced that he had signed a contract with the Wellington Phoenix in the Hyundai A league Australian Competition, bringing him to the capital to play as a target-man. In the highly publicised 2010 pre-season game v Argentina's Boca Juniors in the capital, Macallister scored the opening goal in the 24th minute. Phoenix went on to win 2–1. He scored 7 league goals in 14 starts during his time with the club.
Macallister played for the A-League side Melbourne Heart in their opening game of the 2012/13 season against the Melbourne Victory, which they won 2–1; Macallister scored the winning goal in first half stoppage time. Now also runs a boys soccer team with former Albion Rovers legend Mark Leonard
Macallister was released from Melbourne Heart and joined Eastern Salon in January 2014. He has gained a cult like status in his short stint at Eastern Salon and is affectionately cheered on with the chant, "He's big, he's tall, he's going to score a goal, Macallister, Macallister!"