A first-round draft pick out of UCLA, Tuiasosopo spent his first five seasons in the NFL at various positions on Seattle’s defensive line, including tackle and defensive end. In his rookie season, he racked up eight sacks and was named to the 1979 NFL All-Rookie Team. Tuiasosopo was nominated Seahawks Man of the Year in 1981. In total, he recorded 20 sacks and five fumble recoveries as a Seahawk. In 1984, Tuiasosopo was traded to San Francisco where he played for three more seasons, including their Super Bowl XIX win over Miami.