His research into stem cells contributed to the treatment of spinal cord injuries.

The restoration of mobility to Darek Fidyka, a Polish paraplegic man, used research by Mackay-Sim.

[3] Mackay-Sim was the director of the National Centre for Adult Stem Cell Research at Griffith University before his retirement in 2015.

[8] He attended North Sydney Boys High School.

[8] In 2015,[10] he was diagnosed with multiple myeloma, and was treated with stem cell transplant.