His major works include the Hellman Building, the Hamburger Department Store, Second Church of Christ Scientist and the Eugene W. Britt House.

During this time, the Rosenheim firm designed Farragut Chambers, a ten-story apartment house in Washington, D.C., and various structures in Boston and Worcester, Massachusetts.

The Architect and Engineer of California wrote that the building "universally is considered the finest architectural monument in Los Angeles," built at an unprecedented cost of $1 million.

He also designed Clune's Broadway Theater, the Majestic Theater (on the east side of Broadway between Sixth and Seventh Streets),[4] the Chapman block (at the southeast corner of Fifth and Los Angeles streets),[5] and the buildings occupied by the Farmers & Merchants Bank and the Security-First National Trust and Savings Bank.

[6] The brick mansion he designed as his own residence in 1910, located at 1120 Westchester Place, was considered "one of the finest homes in Los Angeles.

Rosenheim was reluctant to acknowledge the school as modern and wrote the following in the April 1939 issue of The Architect and Engineer:"I do not consider the buildings particularly 'modern' although the administration and assembly hall units may possess something akin to the so-called 'contemporary' style.

After several years serving as the Secretary of the Los Angeles Municipal Arts Commission, Rosenheim was removed following a widely publicized scandal in 1921.

The Rosenheim-drafted plans were then approved at a special meeting of the commission held in Rosenheim's office on a Saturday morning.

[10] Rosenheim insisted he had done nothing improper, but the City Council unanimously voted to remove him,[11] and the local branch of the American Institute of Architects recommended a term of suspension from its ranks.