"My role as a judge involves ensuring that punishment fits the crime."
The move comes as Gallen readies to fight the fine, without the backing of his Cronulla club, who have sided with the game's governing body in an issues that has split much of the rugby league community down the middle.
"No player in the history of the game has been under as much pressure, stress and tension as Paul Gallen over the last two years," Conlon told News Corp.
"None of this or his medical condition was taken into account."
The NSWRL has been pressured by the NRL to sack Gallen as Blues skipper but the state body is standing by its leader.
NSWRL chairman George Peponis has been asked to front the NRL on Thursday to explain his words of public support for Gallen.Both Conlon and Peponis have said they feel for Gallen, who is reportedly suffering from depression and has worn much of the brunt of ASADA's 18-month investigation into Cronulla's 2011 supplements program.
Gallen is serving a back-dated 12 month ASADA ban that ends late next month.
Peponis came out publicly in support of Gallen last week and reiterated those comments in a letter to ARL Commission chairman John Grant.
The NRL confirmed Conlon's exit in a press statement.In the statement NRL head of football Todd Greenberg thanked Conlon for his work as judiciary chairman over the past seven years.
"Mr Conlon has given great service to the NRL judiciary and we wish him every success in the future," Greenberg said.
The NRL will begin the search for a new judiciary chairman immediately.
NRL boss Dave Smith has spoken of his desire to come down hard on player misbehaviour and even rid the game of its bad boys, as evidenced by the exit from the NRL of Todd Carney.
The new head of the NRL integrity unit Nick Weeks has followed Smith's cue as shown by the $10,000 fines slapped on Samoan trio Reni Maitua, Tautau Moga and Sauaso Sue, following their involvement in a Fortitude Valley brawl in the lead up to last weekend's Four Nations double header in Brisbane.
- AAP