Since the first ploughing match was introduced in 1848, there have been many key milestones for the horse competition at the Melbourne Royal Show.
The first trotting contest was held in 1872, first dressage demonstration by mounted police was given in 1923, the Garryowen Perpetual Trophy was introduced in 1934 and in 1939 polo matches were included in the program.
In 1950, novice dressage events were added and in 1952 rodeo events were included in the program.
In 1971 a three day eventing selection event was held at the Show for the 1972 Munich Olympic Games.
In 1993, the Royal Melbourne Horse Show was established as a breed show held in January at Melbourne Showgrounds and in 2002 was moved to Werribee Park National Equestrian Centre.
2007 saw the Equine Influenza and no horses permitted at Melbourne Showgrounds.
The competition now sees more than 2,300 entries and 400 exhibitors each year competing across 380 classes on the Main Arena at the Royal Melbourne Show.
The COVID-19 pandemic in 2020 and 2021 saw the Royal Melbourne Show cancelled.
The Royal Melbourne Show Horses in Action Competition was renamed to the Melbourne Royal Horses in Action Competition in September 2021.