Wilcox replaces Clancy Pendergast as defensive coordinator, Tuiasosopo will coach tight ends and Drevno offensive line.
"These new additions to our staff bring not only tremendous coaching expertise, but they are outstanding recruiters and good, solid people," Sarkisian said in a statement. "They are great additions to the USC football program and the Trojan Family."
Shortly after he was hired Dec. 2, Sarkisian hired Washington assistants Johnny Nansen, Keith Heyward and Peter Sirmon.
Nansen will coach running backs and special teams, Heyward defensive backs and Sirmon will coach linebackers and serve as recruiting coordinator.
Clay Helton will remain as the Trojans' offensive coordinator and Tee Martin the wide receivers coach.
The hirings leave Sarkisian with one opening on the staff: defensive line coach.
Sarkisian has said that he would reach out to
Several draft-eligible defensive players openly campaigned for Sarkisian to retain Pendergast, who molded the Trojans into the
But Sarkisian chose Wilcox, 37, who has worked as defensive coordinator at Boise State, Tennessee and Washington.
Washington ranks 54th nationally and fifth in the Pac-12 in total defense.
Tuiasosopo, 34, played quarterback at Washington and was UCLA's tight ends coach in 2012 before joining Washington's staff as quarterbacks coach this season. He served as interim coach for the Huskies' Fight Hunger Bowl victory over Brigham Young on Friday.
Drevno, 44, was the 49ers' offensive line coach the last three seasons. He previously coached at
Ivan Lewis, Washington's strength and conditioning coach for the last five seasons, also was hired by Sarkisian.