The York seamer was named in the line-up for the YB40 game at Scarborough against Leicestershire, having taken six for 25 against the Foxes in a second XI match earlier this week.
Yorkshire confirmed on Twitter: "Matthew Fisher will become the youngest player to feature in a competitive county match aged 15 years and 212 days."
A youthful Vikings attack also featured Fisher's fellow debutant Ryan Gibson, 17, plus 18-year-old Will Rhodes and 19-year-old Ben Coad, the latter making only his second appearance.
Liam Plunkett returned from injury but Rich Pyrah (hip) and Moin Ashraf (back) joined the rested Ryan Sidebottom and Steven Patterson on the sidelines.
Fisher was named in the matchday squad two days ago, at which point first-team coach Jason Gillespie said: "Matthew deserves his call-up into the squad.
"We monitor the progress of all our players and the feedback I have received from (second-team coach) Paul Farbrace on the way Matthew has been playing has been excellent."
Yorkshire already hold the record for fielding the youngest first-class cricketer after wicketkeeper Barney Gibson, aged 15 years and 27 days, played in the non-county match against Durham MCCU in 2011.