He studied under architect Carl König, for whom he worked during the education as an associate in the König studio.
After graduation from the university, Ehrlich stayed in Vienna, where he worked for Humbert Walcher. Under Walcher, Ehrlich worked on the restoration of the Burg Kreuzenstein. In 1907, he worked on the first project related to his birth city, new government building.
In 1908, Ehrlich undertake work on the adaptation of villa Karma in Clarens, near Montreux.
On that adaptation, Ehrlich worked until 1912. Ehrlich returned to Zagreb in 1909.
In Zagreb he worked at his family architect studio, but in 1910 he was joined with Viktor Kovačić to form Kovačić & Ehrlich studio. Ehrlich cooperation with Kovačić marked in three regulations in Zagreb.
Ehrlich independently worked on the project of regulation of Strossmayer promenade.
The third project from that period was related to the regulation of Vraz walkway. During the Kovačić & Ehrlich collaboration, they realized several residential buildings and family houses. In the 1914, during the work on the Hungarian railroad school Ehrlich was mobilized in the Austro-Hungarian Army.
In 1915, Ehrlich ended his partnership with Kovačić.
After World War I, Ehrlich worked at the Adolf & Ernest Ehrlich architect studio. In the 1920s, Ehrlich designed over twenties residential and commercial properties.
From 1921 to 1923 he worked on the building of Slavenska hipotekarna banka (Slavic Mortgage Bank). After the death of Viktor Kovačić, autumn of 1924, Ehrlich took over construction work on the building of the Zagreb Stock Exchange (now Croatian National Bank) together with Alfred Albini and Stjepan Gomboš.
The work on the exterior and interior was completed in the June of 1927.
In 1925, Ehrlich started to work as the professor at the University of Zagreb Faculty of Architecture. During that time Ehrlich"s studio became one of the largest studios in Zagreb, gathering the most talented generation of architects such as Alfred Albini, Stephen Gomboš, Mladen Kauzlarić, Juraj Denzler and Drago Galić. In 1928, Ehrlich received the invitation for the Congrès International d"Architecture Moderne.
Ehrlich died in Zagreb on September 21, 1936 and was buried at the Mirogoj Cemetery.