Prior to coaching, Manusky played as a linebacker in the National Football League (NFL) for three teams over 12 seasons.

Manusky spent four years as the San Francisco 49ers under 49ers head coach Mike Singletary.

Manusky ultimately accepted the defensive coordinator job with the Chargers, with whom he had previously worked as a linebackers coach.

[5] In the 2018 season, safety D. J. Swearinger publicly criticized Manusky and his play calling following the team's Week 16 loss to the Tennessee Titans.

[6] Despite being one of the better defensive players on the team that season, Swearinger was released the next day by head coach Jay Gruden for his comments against the Manusky.

[7] Manusky left the team among staff turnover after the Redskins hired Ron Rivera as their new head coach following the 2019 season.

After ending a 12-year playing career in 1999, Manusky entered the coaching ranks in the National Football League.