Raduchel's departure from Sun comes just weeks after the Silicon Valley powerhouse lost its top executive for Java technology, the company's key programming language.
AOL Chairman Steve Case hailed Raduchel as an Internet "pioneer" being brought in to provide critical leadership in interactive services.
"His proven abilities at envisioning and forming strategic alliances, and his impressive knowledge of what all businesses need to do to succeed in today's environment, will help us pursue our strategic objectives across the board," Case said in a statement.
Raduchel, a 10-year veteran at Sun leaves on the heels of Sun's long-time executive Alan Baratz, who reportedly had a tumultuous relationship with Ed Zander, Sun president.
Andreessen, who was brought into AOL following its acquisition last fall of California-based Netscape, will be shifted to advisory role at AOL, which is headquartered in Dulles, Va.
Since last year, Raduchel has been responsible for day to day operations and long-term strategy planning for Sun. He handled corporate planning and development, including a recent string of Sun acquisitions.
"We are extremely grateful for the many contributions Bill has made to Sun and to our continued success," Scott McNealy, Sun's chief executive, said in a statement.
Sun and AOL are close. The companies share technology, marketing functions, and house employees in the same quarters in California's Silicon Valley. The two companies started developing Internet technologies together in a project called the Sun-Netscape Alliance, announced in March.
Written By Mike Tarsala, CBS MarketWatch