In only its third season after promotion from club to district cricket, Thornton won the first-grade major premiership in the 1989-90 season by defeating Eastern Suburbs in the semi-final and minor premiers. City United, in the final.
Captained by the experienced Rodney Lawrence, the Thornton first grade team had some outstanding performers in the Gabriel brothers, Peter and Stephen, Allan Wadwell and Trevor Randall. In the final, City United was dismissed for 177 with Stephen Gabriel taking 6-75. In reply Thornton passed the total with only one wicket down with Allan Wadwell scoring 48 and Peter Gabriel 103 not out.
City United won the club championship, as well as the first and third grade minor premierships. Their first grade team, captained by Graham Cannon, had a lot of all-round ability with players of the calibre of Grae Elphick, Stan Leayr, Wayne Trappel, Scott Magann, Scott Preston and Col Macintyre.
Grae Elphick was District Player of the Year with 30 wickets and 355 runs.
The first grade batting aggregate was headed by Paul Johns (Northern Suburbs) with 521 runs, closely followed by Craig Evans (Raymond Terrace) with 514. Leading bowler was Northern Suburbs' Rodney Faulkner with 34 wickets.
In second grade Michael Soper (108 n.o.) and John Warner (177 n.o.) had an unbeaten third wicket partnership of 300 when playing for Eastern Suburbs against Weston Workers at East Maitland.
In the club section Largs had an outstanding season, winning the club championship, the A and B2 grade major premierships and the Cl grade minor premiership. SMR were A grade minor premiers.
Club Player of the Year was Shayne Rumbel who took 70 wickets for Hinton.
In representative cricket Maitland lost the John Bull Shield final to Singleton at Singleton.
Representative Player of the Year was Grae Elphick of City United with 165 runs and 10 wickets in the John Bull Shield competition.
Graham Snedden. (Weston Workers) represented Hunter Valley at tile Under 24 Carnival at Narrabri and was selected in the Combined Zone team.
Following trials at Manilla, Anthony Burgess (Tenambit-Morpeth) went on to be selected for the NSW Under 17 team that played in the interstate championships in Adelaide.
Former Maitland players, Geoff Cooke and Paul Dyson, were selected in the NSW Country team.
Maitland hosted the Quarter-final match of the Tooheys Cup between North-West and Riverina.
Maitland umpire Ray Younger, gained his State umpires' ticket; Arthur Hassett umpired the State Sheffield Shield team v. Country Cavaliers match at Gunnedah; and Max Elphick umpired in the Under 24 Colts Carnival at Narrabri and the Combined Zone match at Wellington.
John McMullen carried out extensive research through the files of the Maitland Mercury to update some of the batting and bowling records of the Association. At a Special Metting at the start of the season the Association became incorporated, thereby giving it an independent legal entity.