SeatonCorp, a privately held Chicago-based staffing provider, reported first-quarter revenue rose 25 percent on a year-over-year basis and that it is on a run rate for full-year 2011 revenue of $400 million.

New client signings and scope/volume expansions helped drive the first-quarter increase in revenue.

SeatonCorp also reported the number of employees, both internal and temporary workers, rose to 20,500 in the past year from 15,500.

The company said its PeopleScout recruitment process outsourcing division posted triple-digit revenue growth. SeatonCorp’s other divisions include Staff Management and StudentScout.