Dimitrios Pikionis was born in Piraeus on 26 June 1887 and was the first cousin of the poet Lambros Porphyra who was a member of the Miaoulis Lodge of Piraeus. In 1906 he became the first (chronologically) student of Konstantinos Parthenis while he was studying at the National Technical University of Athens, where in 1908 he received a diploma in civil engineering. He then went to Munich to study free drawing and sculpture. In Paris, he studied drawing and painting at the Académie de la grande Chaumière.

In 1912, during the Balkan wars, he returned to Greece, enlisted and when he was demobilized he turned again to architecture to complete his knowledge and began his first studies on the architecture of the Modern Greek tradition. In 1921 he was appointed as a curator of Professor Anastasios Orlandos in the course of Morphology of Architecture and Rhythmology, where he remained until mid-1923. In 1925 he was named associate professor at the H.M.P. in the chair of Decorative Arts and was made permanent in 1930.

In 1928, the Pikionis brothers and Theocharopoulos were commissioned with the study for the construction of the Masonic Hall of Athens.

From 1951 to 1957, he was involved in many projects. Among them were the landscaping of the archaeological area around the Acropolis and Philopappou Hill, perhaps his most important project, and the tourist pavilion of Agios Dimitrios Loubardiaris, in pursuit of his ideal, the connection between the ecumenical spirit and the spirit of tradition. The layout of the open spaces around the Holy Rock is a work of art. In 1958, after a 35-year tenure at the NTUA as a professor, he retired.

In 1966 he was elected a full member of the Academy of Athens.

On 28 August 1968 he died in Athens.