The area which is now Mackay City was originally inhabited by the local Yuibera people.
One of the first white settlers to travel through the Mackay region was Captain James Cook, who reached the Mackay coast on 1 June 1770 and named several local landmarks, including Cape Palmerston, Slade Point and Cape Hillsborough. It was during this trip that the Endeavour's botanist, Sir Joseph Banks, briefly recorded seeing Aboriginal people.
In 1860, John Mackay led an expedition to the Pioneer Valley and was the first European to visit the area now named after him.
In 1918, Mackay was hit by a major tropical cyclone causing severe damage and loss of life with hurricane-force winds and a large storm surge. The resulting death toll was further increased by an outbreak of bubonic plague.
The foundation stone of the Mackay War Memorial was laid on the river bank on 18 November 1928 by the mayor George Albert Milton.
It was unveiled on 1 May 1929 by the mayor.
Due to flooding, the memorial was relocated to Jubilee Park in 1945. Due to the construction of the Civic Centre, it was relocated to another part of the park in March 1973.
The largest loss of life in an Australian aircraft accident was a B17 aircraft, with 40 of 41 people on board perishing, on 14 June 1943, after departing from Mackay Aerodrome, and crashing in the Bakers Creek area.
The Rats of Tobruk Memorial commemorates those who died at and since the Battle of Tobruk. The memorial was dedicated on 4 March 2001.
Panoramic image from pathway to Rats of Tobruk memorial in Queen's Park, Mackay
On 18 February 1958, Mackay was hit with massive flooding caused by heavy rainfall upstream with 878 mm of rain falling at Finch Hatton in 24 hours. The flood peaked at 9.14 metres (29.99 ft).
The water flowed down the valley and flooded Mackay within hours. Residents were rescued off rooftops by boats and taken to emergency accommodation. The flood broke Australian records.
On 15 February 2008, almost exactly 50 years from the last major flood, Mackay was devastated by severe flooding caused by over 600 mm of rain in 6 hours with around 2000 homes affected.
Mackay was battered by Tropical Cyclone Ului, a category three cyclone which crossed the coast at nearby Airlie Beach, around 1:30 am on Sunday 21 March 2010. Over 60,000 homes lost power and some phone services also failed during the storm, but no deaths were reported.
The Dudley Denny City Library opened in 2016.