Landfield first exhibited in New York in 1962. He continued his study of painting by visiting major museum and gallery exhibitions in New York during the early sixties and by taking painting and drawing classes at the Art Students League of New York and in Woodstock, New York. He graduated from the High School of Art and Design in June 1963. He briefly attending the Kansas City Art Institute before returning to New York in November 1963. At sixteen Landfield rented his first loft at 6 Bleecker Street near The Bowery (sublet with a friend from the figurative painter Leland Bell), during a period when his abstract expressionist oil paintings took on hard-edged and large painterly shapes. In February 1964, Landfield traveled to Los Angeles; and in March he began living in Berkeley where he began painting Hard-edge abstractions primarily painted with acrylic. He briefly attended the University of California, Berkeley and the San Francisco Art Institute before returning to New York in July 1965.

From 1964 to 1966 he experimented with minimal art, sculpture, hard-edge geometric painting, found objects, and finally began a series of 15 – 9′ x 6′ mystical “border paintings”. After a serious setback in February 1966 when his loft at 496 Broadway burned down, he returned to painting in April 1966 by sharing a loft with his friend Dan Christensen at 4 Great Jones Street. The Border Painting series was completed in July 1966, and soon after architect Philip Johnson acquired Tan Painting for the permanent collection of The Sheldon Memorial Art Gallery in Lincoln, Nebraska.

In late 1966 through 1968 he began exhibiting his paintings and works on paper in leading galleries and museums. Landfield moved into his loft at 94 Bowery in July 1967; there, he continued to experiment with rollers, staining, hard-edge borders, and painted unstretched canvases on the floor for the first time. Briefly in 1967-1968 he worked part-time for Dick Higgins and the Something Else Press.

In October 1969 he had his first one-man exhibition at the David Whitney Gallery in NYC, featuring works of that period which were partially inspired by Chinese Landscape painting. His painting Any Day Now, 1969, 108 x 93 inches was acquired by the Whitney Museum of American Art. His painting Diamond Lake 1969, 108 x 168 inches, was acquired from Philip Johnson by the Museum of Modern Art in 1972 and was installed in the lobby of MoMA for several months. His painting Elijah 1969, 108 x 55 inches was later exhibited in Beijing, China in the early 1990s; and it is currently on view in Havana, Cuba.

By 1970 Landfield was recognized as one of the first painters to have led the “movement away from the geometric, hard-edge, and minimal, toward more lyrical, sensuous, romantic abstractions in colors which were softer and more vibrant.” His paintings were part of the Whitney Museum of American Art’s Annual exhibitions in 1967 and 1969, and he was included in the first Whitney Biennial in 1973. During the late 1960s through the early ’70s his work was included in group exhibitions at the Park Place Gallery, the Bianchini Gallery, the Bykert Gallery, the Sheldon Memorial Art Gallery, the Whitney Museum of American Art, the Museum of Modern Art, the Baltimore Museum of Art, the Studio Museum in Harlem, and the Iris & B. Gerald Cantor Center for Visual Arts (formerly Stanford University Museum of Art) amongst other places. In 1967-1968 two drawings were reproduced in S.M.S. III by the Letter Edged in Black Press, and he was included in New York 10 1969, a portfolio of prints published by Tanglewood Press.

During 1970 Landfield participated in a three-person show in New York City at the David Whitney Gallery and he had solo exhibitions in Cleveland, St. Louis and in Corona Del Mar, California. In 1971 he held his second solo exhibition at the David Whitney Gallery in New York City. From that exhibition his painting Chinese Winter, 108 x 88 inches was acquired by the Rhode Island School of Design Museum of Art, and his painting Storm Thread, 108 x 94 inches, was acquired by the Smith College Museum of Art. Landfield joined the Andre Emmerich Gallery in April 1972 one month after the David Whitney Gallery closed in March 1972.

During the early 1970s to the early 1990s many of Landfield’s major paintings entered important public collections. In 1970 his painting St. Augustine, 1968, 108 x 120 inches was acquired by the Norton Simon Museum in Pasadena; in 1971 Shenandoah (for Eva Hesse) 1970, 90 x 113 inches, was acquired by the Walker Art Center in Minneapolis; in 1972, his painting Rain Dance III, was acquired by the Hirshhorn Museum and Sculpture Garden in Washington, DC, and his painting From Portal to Paradise, 1982, 107 x 78 inches, was acquired by the Metropolitan Museum of Art in 1983, among dozens of others. In 1989-1990 Landfield began correspondence with the late art historian, Professor Daniel Robbins, about the neglected historical understanding of abstract painting in New York since the mid-1960s. Landfield began extensive writing and lecturing about abstract painting from the late 1960s to the mid-1970s.

Landfield traveled throughout the southwest in 1973 and again in 1975. With his wife and artist friends Peter Young and Carmen Megeath he camped, lived and painted dozens of paintings on canvas and limestone in the mountains outside Zion National Park in southern Utah. He taught Fine Arts at the School of Visual Arts from 1975 until 1989. For ten years from 1975 until 1984 four of Landfield’s paintings from the collection of Philip Johnson were installed in the Four Seasons Restaurant in the Seagram Building on Park Avenue between 52nd and 53rd Streets in Midtown Manhattan, on the so-called Mark Rothko wall.

In 1994 Landfield presided over two public panel discussions at the New York Studio School and the Tenri Institute both in Manhattan called Cool and Collected or Too Hot to Handle. In 1995 he curated Seven Painters at the Nicholas/Alexander Gallery in SoHo, an exhibition that featured seven important abstract painters whose careers began in the mid to late 1960s, some of whom hadn’t been shown for many years. In 1996 Landfield had a solo exhibition in Sapporo, Japan and lectured there on American art. In 1997 he aided colleague Ronald Davis’s creation of an educational website highlighting abstract art from the 1960s. He was represented by the Salander/O’Reilly Gallery in New York from 1997 until 2007. In October 2005 he had a solo exhibition of his paintings accompanied by a solo show of sculpture by Peter Reginato at the Heidi Cho Gallery in Chelsea.

In 2007 Landfield had a retrospective exhibition Ronnie Landfield: Paintings From Five Decades, at the Butler Institute of American Art Later that year, he had an exhibition of recent paintings entitled Toward Monochrome at the Heidi Cho Gallery in Manhattan. Landfield has exhibited his work in important institutions and galleries for nearly five decades. Currently he lives and works in TriBeCa, and teaches at The Art Students League of New York; during a recent lecture there he said “It’s important for maximum freedom for an artist, to stay under the radar for as long as possible”. From 2007 until 2016, his work has been exhibited at the Stephen Haller Gallery in New York City and LewAllen Galleries in Santa Fe, New Mexico. He currently is represented by the Findlay Galleries in New York and Florida. He draws, paints and writes left-handed. Landfield’s two sons are artists who live in New York: Matthew Hart Landfield is an actor, writer and director, and Noah Landfield is a painter and musician.

At the time of his exhibition at the Butler Institute of American Art in 2007, Landfield was referred to as “one of the best painters in America and has been since he first came on the scene in the 1960s.” Louis Zona, director of the institute, says “To stand in front of a Landfield painting is to be transported into a world where color feeds upon color and every inch of the canvas is considered … Ronnie Landfield is, pure and simple, one of the best painters in America.”

Most recently, he has been under the representation of Findlay Galleries, and has had his work in several group and one-man shows. In January 2018, he participated in a live discussion with Michael Rips, the director of the Art Students League of New York, about his life and his art at Findlay Galleries.