System One, a Pittsburgh-based staffing provider, acquired Randstad Professionals’ Compliance division, a legal staffing and managed review business. The deal provides a national entrée for System One into the legal staffing and solutions market.

Compliance will operate as a division of System One Holdings LLC. Julian Brown will continue to serve as president of Compliance.

“The synergy between the System One and Compliance business models is remarkable,” said System One CEO Troy Gregory. “We are both fully aligned under a common vision of advancing our clients’ efficiency, flexibility and profitability through exceptional delivery of managed services.”

Gregory has a background in legal staffing, including having served as executive vice president for Hudson Legal. He also served as CEO of Gregory & Gregory and Attorneys on Assignment, two affiliated firms providing recruiting services to the legal community.

System One ranks No. 42 on Staffing Industry Analysts’ 2011 list of the largest U.S. staffing firms.

Terms of the transaction were not announced.