In fact, Olsen and the manager currently in charge of a team the longest, Sporting Kansas City's Peter Vermes, have been at the helm far longer than any other coach in the league. Vermes started coaching Kansas City way back in 2009, and Olsen took over at D.C. in 2010. The next closest managers in terms of tenure didn't begin until 2014.
Add to that three coaches taking over on a permanent basis during the 2018 season and seven bosses beginning their tenure for the upcoming 2019 season, and turnover is far more common than longevity.
As 2019 begins, here's the full list of head coaches in the league, ranked from longest-tenured to newest (year listed indicates a coach’s first season with their club):
MLS head coaches, ranked by tenure:
|Frank de Boer||ATL||2019|
|Marc Dos Santos||VAN||2019|
|Guillermo Barros Schelotto||LA||2019|