Neagu was born in Bucharest. From 1956 to 1959, he studied philosophy and undertook evening studies in technical drawing and fine art whilst employed as a railway cartographer. He was admitted to Beaux Arts Academy, later re-named Nicolae Grigorescu Art Institute, Bucharest, where he studied painting 1960-1965. Neagu had his first solo exhibition at the Amphora Gallery, Bucharest in 1969, gaining international recognition and exhibiting worldwide until his death. Neagu settled in London in 1970, performing and showing his work regularly throughout Britain. He became an Associated Lecturer at Hornsey College of Art in 1973 and an Associate Professor at the Royal College of Art, London in 1976. He continued to teach throughout his career.

Significant solo exhibitions include Brukenthal Museum, Sibiu, 1994; Museum of Contemporary Art, Los Angeles, 1997; Museum of Modern Art, Ljubljana, 2000, and Tate Britain, London 2003. His work has been featured in major group exhibitions including The Condition of Sculpture, Hayward Gallery, London, 1975; Great Gathering of Hyphens, Institute of Contemporary Art, London, 1979; Baroque ’81, Modern Art Museum, Paris, 1981, Drawing Engraving and Sculpture, National Museum of Art, Bucharest, 1996 and Out of Actions - Between Performance and Object, Barcelona, Tokyo and Vienna, 1997.

Neagu received a number of prizes and important international sculpture commissions, including a research and exhibition prize awarded by the Union of Visual Artists and vetoed by the communist authorities in 1969, Durham Cathedral project; Starhead, 1979, On The Strand sculpture competition, 1987 and Century Cross commission, Bucharest, 1991.

Neagu’s work reflects both his personal Romanian history and his relationship with Western art practices. This combination of diverse cultural elements drawn from Western and East European traditions gave his sculpture and drawings great breadth. Neagu also incorporated performance, ritual, and impromptu audience ‘happenings’ into his practice; the results of which informed his sculptural work. When Neagu first exhibited the small scale sculptures (White) Tactile Object with Hinges, and Tactile Object 2, (both 1969) for instance, he suspended them from the walls and ceiling of a darkened gallery. Visitors were invited to feel their way around the room, experiencing the works by touch. Neagu considered sight to be an overused sense. In his Palpable Art Manifesto of 1969 he called for "one public, palpable art through which all the senses, sight, touch, smell, taste will supplement and devour each other so that a man can possess an object in every sense." Many happenings integrated the audience further into Neagu’s practice, often intended to induce a shift in consciousness in the artist through repetitive ritualistic activity, such as the communal consumption of waffles and honey. Underpinning Neagu’s varied artistic practice is a complex, personal thought system utilising symbolism and metaphor to focus on the relationship between human senses and external social systems; the place of the individual in the world. De la Moore la Hirst: 60 de ani de sculptura britanica (From Moore to Hirst: Sixty Years of British Sculpture) 2005