The Padres selected McKee for the honor because of her age and because her late husband was a veteran.
Even though McKee is more interested in ballroom dancing and bridge than baseball, she practiced her pitching with staff members at her retirement home.
"It's very exciting," McKee told 10 News before taking the field. "I'm very honored to be allowed to do that. I have no idea what's going to happen I hope everything goes well. "
By making the traditional throw, McKee became the oldest person ever to toss a ceremonial first pitch at a Padres game.
In addition to appearing on the mound, McKee also planned to eat a hot dog and drink a beer while she was at the park.
"I hope to see the Padres have a winning season during my lifetime," McKee told U-T San Diego.
Although that may never happen, McKee did get to see the home team get a win. The Mets were only able to muster up three hits against the Padres and San Diego won 2-1.