At an early age, Peter entered the office of Ferry & Class as a student-draftsman and remained with the firm several years acquiring valued experience. Later he joined Richard Philipp in organizing the firm of Brusi & Philipp and practiced under that name until 1927. At one time the firm was the largest architectural office in the state with numerous and varied works under construction including many industrial projects, of which the model village of Kohler, Wisconsin, United States was the most noted. In addition, Mr. Brust was connected with the designing of a large number of churches, schools, residences, department stores, and institutional buildings.
A period of independent practice followed the termination of the partnership in which he was the architect of two distinguished churches, St. John's at Kohler, and the Chapel of St. John's Convent at Milwaukee.
Prominent professionally throughout a long career he was elected to the Wisconsin Chapter in 1911 and later served two terms as president. In 1923 he was made a Fellow of the Institute and between 1940-1943 was Regional Director representing the districts of Illinois and Wisconsin. Also active in municipal affairs, Mr. Brust was a member of the Art Commission, the Metropolitan Park Commission, served twenty-five years on the State Building Code Advisory Committee, twenty years on the Board of Appeals on Zoning, and had been on the State Board of Examiners of Professional Architects and Engineers over a long period.