A retired National City Bank officer, Mrvan served 10 years on the Hammond City Council, including several years as the council's president, before being elected to the State Senate in 1978.

Mrvan currently serves as the ranking Democrat on both the Senate's Ethics and Insurance and Financial Institutions Committees and is a member of the Education & Career Development and Commerce and Economic Development standing committees as well as the Financial Institutions Subcommittee.

Mrvan has also been appointed to serve on the Communications, Financial Services and Interstate Commerce Committee and the Human Services and Welfare Committee of the National Conference of State Legislatures, a bipartisan organization that serves the legislators and staffs of the nation's 50 states, its commonwealths and territories.

A veteran of the U.S. Air Force, Mrvan attended Indiana University and the American Institute of Banking. He and his wife, Jean, reside in Hammond and have three adult children.