Dankmar Adler was born in a small town in Germany. After his mother died in childbirth, his father named him Dankmar which is a combination of the German words dank (thanks) and mar (bitter). Dankmar moved with his father to Detroit, Michigan where his father became the rabbi of Congregation Beth-el. He did not finish his formal education but instead chose to become a draftsman in the office of Detroit architect E. Willard Smith.
At the age of eighteen, Dankmar enlisted in Company M, First Regiment, of the Illinois Light Artillery to fight in the Civil War and served in the Chattanooga and Atlanta campaigns. He spent the last portion of his service in the Engineer's Office, receiving training in architecture and engineering. When he was discharged, Adler returned to Chicago and joined architect Edward Burling in designing churches, schools and courthouses. The 1871 Great Chicago Fire caused a building boom and the commissions Burling and Adler received quickly grew to include offices and large public buildings. In 1872, Adler married Dila Kohn, the daughter of Abraham Kohn, founder of the Kehilath Anshe Ma'ariv Synagogue where Adler's father was the rabbi.
In 1879, Dankmar decided to leave the partnership with Burling and open his own firm. He asked young designer Louis Sullivan to join his firm and soon after they became partners. In 1886 Adler and Sullivan were commissioned by Ferdinand Peck and the Chicago Auditorium Association to design the Auditorium Building. After nearly twenty years, Adler left the firm in 1895. He died of a stroke at the age of 56, five years later.