Thought of your couch when I saw this article.

https://www.housebeautiful.com/room-decorating/colors/g1185/mint-rooms/

I would do very dark purple. Eggplant.

My daughter has a sofa that is green and she found paint that matched the sofa! I would suggest a softer mint green with bright white trim or if you would like a darker room, try a darker green (My bridesmaids wore mint green gowns and the groomsmen wore dark green tuxes with mint green shirts).

Thank you for these amazing suggestions!!

I have never seen a couch that color. Really neat. I think I would opt for stark white walls in flat paint and paint mouldings in the same white color but gloss finish. Accent the couch with emerald geeen velvet pillows,white faux fur, hot pink or cobalt blue. I think an Art Deco type coffee table would complete a great room. Are drapes out of the equation? i might consider a floor length drape in a print similar to posters rug suggestions. Good luck.

Ohhhhhh, guys tried all colors. Nothing left to mock up.

Love the dark green wall mock up!!

here is inspiration

I'm leaning toward a smoky gray. A true gray, not taupe or beige.

Try Benjamin Moore Shadow Gray. 2125-40. Photo is not loading for some reason.

I looked at BM painting site for mint color, what colors are going with it.

And got that Polaris Blue is one of them.

and also

Here is my mocking up

My favorite bathroom had mint green walls and chocolate brown checked curtains and skirt around the wall-hung sink - looked like an Andes mint and always relaxed me (or made me crave one!) If you like candy, go for candy colors.

How many rectangular moldings are there? so you want to accent them?

A wallpaper that subtly combines a couple greens, maybe leaves / and a light neutral I'd photoshop.... if not painting.

A room similar:

And what other colors are in your house?

Fabric can be starched [?] onto a wall - same fabric for nearby roman shades?

A delicate -

"Dollie II" (4-Pack) Removable Wallpaper Panels 24"x48" · More Info

https://www.houzz.com/products/dollie-ii-4-pack-removable-wallpaper-panels-24x48-prvw-vr~141623163

Contemporary Whimsical Woods Scene Wallpaper, White, Bolt · More Info

https://www.houzz.com/products/contemporary-whimsical-woods-scene-wallpaper-white-bolt-prvw-vr~101489948

Your paint appears fine from here - a barely there pattern could work well with a lamp in corner …

the room can handle a strong wallpaper or mural with your mint green sectional.

https://www.muralswallpaper.com/shop-murals/green-vintage-tropical-minimalist-wallpaper-mural/

https://www.thibautdesign.com/catalog/product/details/product/janta_bazaar_t64162/material/wallpaper/colorway/citron_green_AB/

https://www.amazon.com/Blooming-Wall-Non-Woven-Livingroom-Multicolor/dp/B0724ZTMZQ?ref_=fsclp_pl_dp_2

Celerygirls' deep blue shades are really doing it for me.

Any thought as to windows, and if they enter the pic? would they blend with new paint color - I'd think so, but we haven't seen the whole room [?]

Are there still Frango Mints now that there is no more Marshall Fields?

Not a Pro.

I actually like your wall color and I love the idea of adding purple or eggplant as an additional color, but not on your walls.

I would go a big and bold print on your window drapes that contain mint, purple and more. Adding an area rug, I would go solid there. Possibly a shade of purple.

Some inspiration:

Chelsea Apartment · More Info

Greenwood Village Home · More Info

Speaking of Marshall Fields, to tell you how long ago I was last in Chicago, a few years ago someone I knew in Chicago was getting married and I said, "Oh, how exciting you get to register. The easiest way to look at the largest selection is to just go down to the Great Wall of China at Marshall Fields."

And I received a "Whaaaat?" in response.

My pick would be the tone on tone mock up. Picture 5 from Beverly. The different shades of green look understated but classy. I to do like the idea of including purple in your room. The two colors seem to play well together in your space.