[3] Irvis moved to Baltimore, Maryland, where he taught English and history in high schools until World War II.

In 1950, he left his businesses and pursued blue-collar work in steel mills and road construction, to earn money in order to go to law school.

He worked as law clerk to Judge Anne X. Alpern, was hired as Pittsburgh city solicitor, and advanced to become the second black assistant district attorney of Allegheny County, Pennsylvania, the first being Oliver Livingstone Johnson who was appointed in February 1942 by District Attorney Russell H. Adams.

Irvis entered politics and was elected as the state representative from Pittsburgh's Hill District, serving in the legislature for 15 straight terms.

He is also largely responsible for the Pennsylvania House Ethics Committee, lobbyist registration, and the Legislative Audit Advisory Commission.

In 1988, the same year that he retired from politics, Irvis published collected poems under the title This Land of Fire (ISBN 0-943556-01-5), issued by Temple University.

On March 25, 2013, the Community College of Allegheny County hosted a ceremony for the newly completed K. Leroy Irvis Science Center, named in honor of his work in helping to establish the community college system in Pennsylvania and for his long career of service on behalf of Allegheny County.

[8] The University of Pittsburgh Library System, Archives Service Center maintains a large collection of wide variety of material related to Irvis's life, career, and political activities.