His first one-person exhibition was at the Rowan Gallery, London, in November 1965, where he had many subsequent shows, as well as at the Betty Parsons Gallery, New York, in 1972 and 1974. In 1974 his "Paintings Cambridge/New York" was organized by Richard Francis, at the Walker Art Gallery, Liverpool. His work was included in many international exhibitions organized by The British Council, including the Paris Biennale and "British Painting and Sculpture 1940 to 1970" at The National Gallery of Art, Washington, DC, 1970. He made a series of prints with Kelpra Studios Tate) and Editions Alecto in London, and in New York at Simca Studios which were exhibited at Multiples gallery, New York.
Invited to be the first Artist in Residence at King's College, Cambridge from 1968 to 1970, he became friends with E.M. Forster, Dadie Rylands and other Bloomsbury survivors including Duncan Grant, whose decorations in King's for Maynard Keynes he had restored, in rooms then occupied by Bernard Williams. His paintings refer to the ambiance of Cambridge, the architecture of King's, and bear the mark of American Modernist art as well as references to "pop" imagery, and his own photography. Examples include : "Cambridge Green" (Tate Britain) and "Cambridge Red and Green" Pallant House Gallery Colin St John Wilson Gift, and "James Gibbs", named for the architect of the Gibbs building where he lived. A notable painting referencing the assassination of President John F Kennedy, called "Zapruder" (1967) is in the collection of the British Council.
In 1985 he temporarily returned to England, to Sandgate, Kent. In 1987, following the sudden death of Andy Warhol on February 22, he made in one year close to 200 small paintings, collectively titled "Post-Warhol Souvenirs", which all featured references to Warhol's "Marilyn" image. They were exhibited at the Mayor Rowan Gallery in London in 1988, opening on February 22, 1988, the first anniversary of Warhol's death. Marco Livingstone wrote an article on them for the magazine "Art & Design", and they were featured in his book "Pop Art, A Continuing History" Thames and Hudson. Several of these paintings are in the collection of the Pallant House Gallery, Chichester, and the Berardo Foundation, Portugal.His Newcastle days and first New York visit are described in some detail by Michael Bracewell in his book Re-make/Re-Model, 2007, about the founding of the group Roxy Music
Back in the United States, he lived in Miami, Florida and Jamestown, Rhode Island, before returning to Florida.
Frequently visiting New York in the years following 1964, Mark Lancaster moved to the United States permanently in 1973. He became an assistant and Private Secretary to Jasper Johns from 1974 to 1985.
In 1975 he started working as Resident Designer with the Merce Cunningham Dance Company. Over the next 10 years he designed sets, costumes and lighting for the following dance works: "Sounddance" (1975), "Rebus" (1975), "Torse" (1976), "Squaregame" (1976), "Fractions" (both video and stage versions, 1977), "Tango" (1978), "Roadrunners" (1979), "Duets" (1980) "Tens with Shoes" (1981), "Gallopade" (1981), "Trails" (1982), "Quartet" (1982) "Roaratorio" (1983) "Inlets 2" (1983) "Fielding Sixes" (1983), "Pictures" (1984) and "Doubles" (1984). He also designed "Duets" for the American Ballet Theatre (1982), "Fielding Sixes" Ballet Rambert (1983) and Ballet Royal de Wallonie (1983).
In 1984 he retired as Artistic Advisor to the Merce Cunningham Dance Company , but returned in 1988 to design "Five Stone Wind",in Berlin, Avignon and New York, for which he received a 1989 Bessie Award New York Dance and Performance Awards, and in 1991 to design "Neighbors", in 1992 "Touchbase" for Rambert Dance Company and the Cunningham Company, in 1993 "CRWDSPCR", and in 1994 new versions of "Sounddance" and "Rune".
Mark Lancaster currently resides in Miami Beach.
He became an American Citizen in 1999.