He studied at the Riga art school by J. Rozentals (1945 – 49), in the Riga craft secondary school (1945 – 50). In 1962, he graduated from Department of painting of the Latvian State Academy of arts with the thesis "brocēni" (under the guidance of E. Kalnins).
L. Kuptsis worked as a scene painter at the Youth theatre (1955 – 56), the artist in cinema "Pionieris" (1962 – 64), artist Director of the group in a TV movie (with 1964).
In exhibitions the artist has participated since 1956.
Personal exhibitions are organized in Jurmala (1969, together with P. Dushkin), Riga (1972, together with A. Artum, A. Junker, L. Davidova - Medna).
Memorable exhibitions are organized in Riga (1978), Koknese, Kuldiga, Saldus, Jekabpils (1978),Valmiera, Aluksne, Ventspils (1979).
Since 1968 he is a member of the Union of artists.