At the age of 12, Selldorf's father purchased a house in Cologne, Germany, making tiny adjustments to the lighting, furniture, and wall color that formed the foundation for her own architectural approach.

[19] Selldorf is a sought after architect in the art world, designing a plethora of gallery spaces, museums, and homes for both artists and collectors.

"[24] Her work has also been praised by Paul Goldberger, Architecture Critic for The New Yorker as "...a kind of gentle modernism of utter precision, with perfect proportions.

"[25] In another article by Architectural Digest, Selldorf describes her design process—as demonstrated in her work on a Fifth Avenue apartment—as focusing on "unconscious comfort" and "clean and clear space.

The German-born Annabelle Selldorf runs the firm, which stresses crisp lines, elegant volumes and a clean, formal vocabulary in which nothing goes to waste.

[34] The Sunset Park Material Recovery Center opened on the eleven-acre 29th Street Pier in the South Brooklyn Marine Terminal in December 2013.

[45] With an understanding that the more environmentally friendly option (barge transport rather than truck) still has negative impacts on the location's aquatic environment, the Center installed fuzzy ropes alongside its mooring pier to support mussels, which purify water.

[44] The addition of New York City's first commercial wind turbine and a large solar array not only allow the center to lower operational costs, but also keep sustainability in mind.

[47] The seven-story residential structure is in line with the rooflines of the rest of the area, but its exterior, composed of prefabricated terracotta sections, weathered steel, glass, and wood, sets it apart from the neighborhood's other low-rise buildings.

[49] One of the two-bedroom residence's interiors was designed by Selldorf Architects, featuring warm-toned mid century furniture to play off of the modern architectural elements, building's warm hued exterior, and plethora of natural light.

[55] Seldorf took heavy inspiration from the craftsmanship of Steinway pianos, as “end-grain oak flooring mimics that of Steinway’s factory in Queens; the patter of the lattice ceiling panels incorporates the shape of a grand piano; and imperial-yellow upholstery on the recital hall’s 74 seats echoes the hue of the felt found inside the instruments.”[56] The main focal point of the showroom, however, is the main staircase which houses an installation by artist Spencer Finch titled Newton's Theory of Color and Music.

While many of Annabelle Seldorf's gallery and museum designs take after the modern ‘white box’ model of exhibition spaces, the Neau Galerie's historic charm was highlighted.

For example, ramps were added to the exterior of the building, and the interior received an elevator in order to make the museum accessible to a greater number of visitors.

While the space could have easily been renovated into a blank canvas, Selldorf decided to restore the original wood ceilings and steel trusses.

[64] In July 2021, Selldorf emerged as the winner from an international shortlist of six firms to lead a design team for a major building project of London's National Gallery, including an upgraded foyer in the 1991 Sainsbury Wing, a new research centre in the lower level of the main 1838 Wilkins building and improvements to the outdoor space on the edge of Trafalgar Square.