Lalewicz finished school at a gimnazjum in Suwałki in 1895. He then studied architecture at the Academy of Fine Arts in Saint-St. Petersburg, from which he graduated in 1901. He continued his studies in Sweden, Norway, Germany, Austria and Italy.
Until 1917, he taught the history of art and the history of architecture in Saint St. Petersburg schools, while at the same time designing various buildings in Moscow and Saint St. Petersburg.
After World War I he moved back to newly independent Poland. Between 1925 and 1927 he was the dean of the Architecture Department at the Warsaw Polytechnic, and between 1935 and 1938, he was a rector.
He was active in various social organizations dedicated to the preservation of historic buildings.