Roy Dominguez started his initial employment at Inland Steel where he worked as an apprentice millwright in Local 1010.

In 1976, Roy enrolled at the Indiana State Police Academy. A year later Roy Dominguez graduated first in his class and won the prestigious Donald Flint Award for outstanding cadet.

As an Indiana State Trooper he attended night classes at Indiana University Northwest and earned a BA in sociology. Dominguez enrolled in Valparaiso University School of Law.

Once Dominguez received the law degree he joined the Lake County prosecutor's office in 1982 and was named Deputy Director of the Child Support program. He cracked down on dead-beat parents and increased child support collections 300%, from $3 million to $9 million.

In 1989 Governor Evan Bayh appointed Roy as chairman of the state Workers' Compensation Board. Under Roy's leadership, the Worker's Compensation Board was modernized and outdated workers' comp. laws were overhauled for the first time in 62 years.

Roy has served as legal council to many municipalities and boards.
On January 1, 2003 Dominguez assumed the Office of Lake County Sheriff.