Official League Records
The remainder of this article contains lore created collaboratively by the Blaseball community.
Professional Glolfer Career and Conversion to Blaseball
Official records indicate that Jaylee was a professional Glolfer who renounced that profession a fair way into the XX67 season, shortly before the Blaseball-Glolf Clonflict. Jaylee has contradicted this version of events, noting that her defection actually occurred "at the end of the war," making her the only known survivor from the Glolf side of the Clonflict. In either case, little is known about her former career, as all records of Glolf have been eradicated.
Since no Glolfer had ever made such a conversion before, there was no precedent to follow, leading to a rough transition period. Official league records report the convention of a Blaseball Tribunal which included representatives from the Umpires, the Players, and the Concessions Workers. This tribunal set out to determine what conditions they deemed necessary and sufficient to accept Jaylee as a Blaseball player. For her part, Jaylee claims there was no such representative body, offering vaguely that she aimed to "negotiate an end [to the war] with Blaseball leadership," but was "misled" as to key provisions of the agreement.
Both accounts agree that the bargaining included key pieces of information that decisively shifted the balance of the Clonflict in Blaseball's favor (see e.g. the flammability of Glolf scorers and judges). League records state that following the exchange of information, the Tribunal allowed Jaylee to become a Blaseball player if she agreed to completely renounce the splort of Glolf, to which she "quickly agreed without coercion or threat." Jaylee's account contrasts, noting a "nontrivial amount" of coercion and threat. She quickly recanted this testimony under penalty of incineration.
As part of the transition, Umpires destroyed most of Jaylee's Glolf-related paraphernalia; however, she successfully negotiated to keep her Glolf cart after painting over the "Glolf" part because "that way it's just a cart, and who doesn't love a cart?", as well as her pitching wedge, which she is allowed to use on the mound, since "the word 'pitch' is right in there."
Jaylee was admitted as a full Blaseball player shortly thereafter, joining the Dallas Steaks. Her teammates, initially unsure of her true loyalties, have grown to trust Jaylee after playing with her for multiple seasons, and consider her a Blaseball player through and through. [How wrong they are.]
The Pitching Wedge
The debate around Jaylee's pitching wedge was an especially hazardous part of Jaylee's conversion and early participation in the league. Many claimed that such an instrument would tarnish Blaseball forever, resulting in the return of Glolf and undoing the decisive victory of Blaseball in the Clonflict. Blaseball leadership ultimately ruled that Jaylee would be allowed to continue using the pitching wedge, so long as she never again used it to strike a Glolf ball. Since all other Glolf paraphernalia were destroyed following the resolution of the Clonflict, this condition has so far proven trivial.
Jaylee delivers all of her pitches by striking the ball with her pitching wedge. Since various grips are notably more difficult with this method, she has been forced to use a variety of different techniques to emulate the standard Blaseball pitches, including:
- Teed-Up Sinker
- Drop-'n'-Hit Curveball
- "Cool Bouncy Trick With The Head Of The Club And Then Hit It Mid-Air, Like What Tliger Irons Did" Fastball
All of these pitches must follow the standard rules of Blaseball, giving the hitters a fair chance at hitting them if they are called a strike. Since the various pitches each require wholly distinct techniques to deliver them, Jaylee's pitches are famously easy to read. Their allowance in the game has been deemed by opposing players "unnerving, but fair."
Rumors of Possession by Mostly-Dead Glolf Gods
Jaylee's permanent residence is a former championship Glolf course, notably the site of REDACTED.
[One day they will burn as we have burned.] 
Ronan Jaylee's Season 5 Tlopps Card by @JoshCloss