Police said the man and woman had just left their car and were walking into the Starbucks in the 10700 block of SE 208th Street when the shooting occurred.
"They were coming as customers, and as he opened the door, she pulled the weapon and opened fire," said Asst. Chief Derek Kammerzell with Kent Police.
Witnesses, including an Army Vet, rushed to the wounded man, who was bleeding profusely from the cheek.
"I asked people to grab gloves and towels and help put pressure on the wound until paramedics arrived," said Michael Tyler.
Police said the victim managed to convey to witnesses who shot him despite his massive facial wound.
"(We asked) what's your name, who did this, do you know her," said Sam Labberton. "And he was like, 'yes I do', threw me his phone, gave me his passcode and we got her name and gave it to the cops."
The woman had jumped into an SUV and left the scene. But a few hours later, the woman turned herself in to Tacoma police and was arrested.
The extent of the victim's injuries were not immediately available, but he was reportedly conscious when treated by medics.
Investigators are still looking into the relationship between the man and woman and a motive for the shooting.