The 21-year-old is yet to make his senior debut for the Cottagers but has gained experience playing for Fulham's under-21 side in the EFL Trophy. His move to York makes him the club's ninth summer signing since securing promotion back to League Two.
McNally could make his competitive debut for the Minstermen in the EFL Cup preliminary round tie against Crawley Town on Monday, 3 August, giving him an early opportunity to stake a claim for regular game time at his new club.
The loan represents a significant step for the young goalkeeper, who will be hoping to use the season to build senior experience away from Craven Cottage after progressing through Fulham's academy setup. York's recruitment drive this summer reflects their ambitions following promotion, with the club looking to strengthen across the squad as they prepare for life back in the fourth tier.
York will be hoping McNally can settle quickly into life at the club, with competitive fixtures now only weeks away. The EFL Cup tie against Crawley offers an early marker for where he stands in the goalkeeping pecking order, though the club's summer business suggests a settled group is beginning to take shape ahead of the new campaign.
For Fulham, sending McNally out on loan continues a pattern of allowing academy prospects regular first-team football elsewhere before assessing whether they have a longer-term future at Craven Cottage. The Premier League club will monitor his progress at York closely over the course of the season, with a strong campaign potentially strengthening his case for a route into contention back in west London further down the line.
The move also gives York a goalkeeper with Premier League academy grounding to add competition and depth to their squad, an area of the pitch the club has clearly prioritised as part of their broader summer rebuild following promotion.