Having a nationalist perspective, Eldem dedicated his life to taking innovative steps for contemporary Turkish architecture and creating a modern language in Turkish architecture. He began his architectural practice with the "Turkish Pavilion" exhibited at the Budapest Fair in 1931; he signed his name to significant works such as the Yalova Thermal Hotel, Istanbul University Faculties of Science and Letters, Harbiye Hilton Hotel, Taksim Atatürk Library, Rahmi Koç House, and Uşaklıgil Mansion.

The Ayaşlı Mansion, which he built on Büyükada, is considered a reflection of his ideas on the Turkish House. This structure, featuring the traditional 'Karnıyarık' (central hall) house type, is based on a sofa plan with two facades. It possesses a striking architecture with its horizontal roofline, wide eaves, vertical windows, and characteristic four-column design. Additionally, the Rıza Derviş Mansion he built on Büyükada is another important work designed by blending the idea of the Turkish House with modern architecture through its 'L-type' plan.

In small-scale projects such as houses, residences, and cafes, Eldem pioneered the prominence of traditional motifs by prioritizing traditional architectural forms. In more comprehensive projects such as hotels, banks, offices, administrative, and educational buildings, he adopted rationality and functionality, emphasizing material and structural system requirements. He generally preferred to use traditional elements in formal details.