Step One: Separate Rooms, Complete Setups
Begin with the newcomer in a single room containing everything: litter tray, food, water, scratcher, bed, toys, and a proper hiding place. Your resident cat keeps the rest of her territory untouched. Visit the newcomer for play and company, wash hands between cats, and let both settle into eating and sleeping normally before changing anything — rushing step one is the commonest cause of introductions that stall later.
This stage has no fixed length. A confident young newcomer may be ready to proceed in days; a shy rescue may need weeks, and that patience is the introduction working, not failing.
Step Two: Scent, Then Meals at the Door
Exchange scent with cheek-rubbed cloths placed near each cat's bowl, swap bedding, and let each cat explore the other's empty space while its owner is shut elsewhere. When scent draws sniffing rather than alarm, start feeding both cats either side of the closed door between their areas, bowls set back far enough that both eat relaxed, edging closer over days.
Door meals are the engine of the whole process: twice a day, the stranger's smell and sounds arrive together with the best event in a cat's schedule. A cat who will not eat near the door is not ready for eyes on the stranger, however long the calendar says this step should take.
Step Three: First Sight Through a Barrier
Open the visual channel while keeping bodies apart — a mesh screen, stacked baby gates, or a door wedged a crack and secured. Pair these sessions with meals or parallel play, keep them short, and position bowls and toys at whatever distance lets both cats stay loose-bodied. Expect some hissing and puffed tails at first sight; the question is recovery. Cats who hiss, then return to eating, are learning. Cats who fixate, yowl, or try to attack the barrier need more distance and a return to door meals for a few days.
Swap which side of the barrier each cat is on occasionally, so the newcomer also experiences the wider home and the resident experiences the newcomer's room and its smells.
Step Four: Supervised Meetings With Exits Open
Choose the largest, most escape-friendly room, remove breakables, and let the cats in without carrying either — open doors and let them walk. Stay calm, keep treats and toys flowing for relaxed behaviour, and let a cat who leaves, leave. End sessions while they are still boring, and separate the cats again between meetings at first, extending shared time only as the dull, promising behaviours accumulate: eating in sight of each other, grooming, choosing a nap spot in the same room.
Intervene early and quietly if you see stalking, blocking, or one cat cornered — distract with a tossed toy and let the pursued cat exit. A genuine fight means a full reset to separate rooms and a slower rebuild, and repeated fights despite patient staging are a reason to involve your vet for advice or referral, not to persist harder.
Step Five: Shared Life, Managed Resources
Full integration is not the finish line; it is the start of ordinary multi-cat management. Keep one litter tray per cat plus a spare in different spots, feed apart until you are sure neither guards food, and keep duplicate perches, scratchers, and hiding places so daily life never forces a contest. Keep the newcomer's room available as a retreat for the first weeks of freedom — many cats use it long after they technically have the whole home.
Track the milestones and the setbacks somewhere everyone in the house can see them, because introductions unravel when one person skips a stage another was carefully holding, and KinsLe Family Sharing keeps both cats' profiles, routines, and stage notes in front of the whole household, so the cat who sets the pace gets the same handling from everyone.