Baseball in Campbelltown began in 1956 after a group of mostly local cricketers got together and formed the Campbelltown Colonials Baseball Club. The Club's colours were navy blue and yellow.
The Colonials started off in the Cumberland Baseball Association’s C Grade competition and the following year won their first Minor Premiership and Premiership.
From 1956 until 1964, the Colonials were only a one-team Club with their home ground at the Campbelltown Showground.
In 1965, a second team was registered, coinciding with the Club’s move to Hurley Park which remained the Club's home ground until 1980. In 1968 the Colonials first fielded a junior team.
Three years later, the Colonials accepted Campbelltown City Council’s offer of a still-to-be-developed site in Woodlands Road, St Helens Park, as their future baseball-dedicated home ground.
At this time, 'Woodlands' was regenerated bushland, having previously been used for cattle grazing and orchards. Use of the land as a waste management facility began around the mid 1970s.
By 1972, the Club had grown to four Senior and three Junior teams, stretching the one diamond at Hurley Park to its limit.
As a consequence, the Juniors moved to their 'second' home ground which was unnamed but referred to as being 'behind the old Town Hall' (today's Town Hall Theatre) and the Good Intent Hotel . Today this area is occupied by the Campbelltown Mall and Koshigaya Park.
By 1973, with only one or two Colonials from the 1950s still playing, and only a few more from the early 1960s, the game was transitioning from a Winter to a Summer sport. At this time, the Colonials were morphing into the Campbelltown Ghosts.
In the 1973-74 Summer season for Seniors, the Ghosts played for the first time in the NSW Baseball League's Major Summer competitions.
In the 1974 Winter season, Colonials played for the last time in the Cumberland Baseball Association - the last time the name Colonials was used, leaving only the name Ghosts.
The Juniors moved to Summer baseball in 1971-72 and took the name of Ghosts from 1974-75 onwards.
Under the Colonials name, 40 Seniors teams had played in the Cumberland Baseball Association competitions since 1956, winning seven Minor Premierships and seven Premierships.
In the Juniors' seven years as Colonials, 20 teams were fielded with one Minor Premiership secured.