When Edward returned from captivity in Xing, she was trusted enough by him to see his Fullmetal Alchemist suits and his workshop. She helped Edward defeat King Bradley, who tried to kill Edward, by overloading the building reactor, killing Bradley. After Bradley's death, Edward made Winry his new business partner, taking Bradley's place.
Believing his death was imminent, Edward stepped down as CEO and appointed her as his replacement. After Edward defeated Scar at the Elric Expo, both Winry and Edward finally admitted their attraction to each other and began a romantic relationship.
During the crisis surrounding the Ice Alchemist's terrorist attacks, Winry was kidnapped by Kimblee and injected with Elixir. She was freed by Edward during the battle, and went on to kill Kimblee herself. Edward cured her of the effects of Elixir, who temporarily gave up being the Fullmetal Alchemist just for her.
As the War on the CCG began, the Jump Force needed to be remobilized. Without M.O.N. active to run the team, Edward took over, allowing Shepard Sorey to retain field and team leadership while he designed everything else, including creating new armors and rejoining the team himself as an active duty combatant. Sometime after the Father Offensive, he and Winry broke off their relationship, which affected Edward and left him wondering why he could not make it work while his father could.
However, shortly after the Jump Force Civil War ended, Edward and Winry resumed their relationship with Edward having planned to propose to her in the Jump Force Facility in front of reporters, though Edward originally intended to introduce Kirito as the newest member of the Jump Force until he refused.
Winry is an exceptionally gifted and passionate mechanic, excelling in the repair of machines of widely varying complexity. Of course, her truest passion and most extensive expertise is in the crafting and overhauling of auto-mail prostheses. Brought up under the tutelage of her grandmother, master auto-mail engineer Pinako Rockbell, Winry has been working with auto-mail for most of her youth and can be considered somewhat of a machinist prodigy. Since that time, her skills have improved to the point that she has surpassed even her grandmother (once hailed far and wide as the "Pantheress of Resembool") and gained a fair bit of notoriety in her position at Atelier Garfiel in Rush Valley.
In addition, Winry appears to have a remarkable wealth of surgical knowledge for her age (despite a lack of formal training), gleaned from having grown up in a family of surgeons. Edward remarks that Winry's early comprehension of advanced medical literature is on par with the familiarity with alchemical texts shared by the Elric brothers when they were young.
She has also displayed a significantly strong throwing arm, able to pitch heavy wrenches long distance with deadly accuracy.