Kipniss's early work consisted of abstractions, biomorphic forms, landscapes, cityscapes, still lifes, and figures. The majority of these works were landscapes of subdued color, often with few details, and loosely brushed. Large Trees at Dusk (1962) was one of several paintings and drawings in 1961 and 1962 which introduced a boldness of form and a more pronounced moodiness.

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The paintings and prints that followed, executed either in black and white or in color, include numerous variations in the shape, size, and placement of trees. Large Trees at Dusk exhibits the beginning of Kipniss's purification of tree forms, his use of closely related hues in a subdued or dark range, and the sense of solitude characteristic of his mature output. Of the paintings and prints since 1962, hundreds show the interplay of tree trunks, focusing on close or more distance views.

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In a review of the artist’s 1966 solo painting show at The Contemporaries, Time magazine wrote: "In the twilight zone between recollection and imagination, a New York painter has found a vista of mind and mood that he calls ‘the Inner Landscape.’ With hushed tones, feathered brushing and eerie chiaroscuro, he invests his scenes with the appearance of reality and the ambiance of dream." (“Art in New York,” Time, Feb 4, 1966: E2) Kipniss’s paintings in the late 1960s often exhibit vibrant, jewel-like undertones that lend pulsing energy to the composition and his rugged brushwork.

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In the 1970s and 1980s, Kipniss developed his mature style, composing his forms and spaces separately, working on each alternately after the paint has dried. He brushes between them and recomposes each area more than once, sometimes with five or six passes in order to get "the varied parts of the image to mesh together.” Continuing his exploration of landscape and its relationship to human experience, his brushwork began to be more refined. His palette also morphed to warm ochres, brick reds, and deep green earth tones. He often composed detailed studies of residential settings at the edges of open, undeveloped areas, seen at a distance. Fences and outbuildings often punctuate the scene.

 

In the 1990s and early 2000s, Kipniss frequently turned to interior scenes, and his style once again shifted. His compositions of this period are atmospheric and moody, depicted in a palette of dark, cool colors. Forms are stylized, lacking detail, and there is an intense focus on the effects of light and shadow. The scene is set as within a domestic structure, with the landscape showing just beyond, through a window. Elements of the natural world are juxtaposed with plants and arrangements of flora as viewed from indoors; the two realms seem to meld in compositions such as Clear vase & landscape (1995) and Interior w/ leaves (1999). 

In Kipniss’s late phase, from 2000 to 2018, he returned to landscape, favoring a hazy pastel palette. Splash III (2003) and A celebration of morning (2007) are examples of Kipniss's paintings of this period which center trees extending into grassy landscapes, often in different effects of light. These paintings display his use of closely related tones, a strong accent on the purity of form, refined silhouetting, and pronounced luminosity.