Despite Derek Hale being a fan-favorite character, actor Tyler Hoechlin exited Teen Wolf after season 4. Loosely based on the 1985 film of the same name with Michael J. Fox, the MTV show debuted in 2011 and wrapping up in 2017 featuring an ensemble cast led by Tyler Posey playing the titular role - a teenage werewolf called Scott McCall. The show amassed a loyal following, but Teen Wolf has had problems keeping its main cast intact. with a series of departure during its middle seasons. One of them is Hoechlin, who left the show in 2014.
Hoechlin played one of the main characters of the series, Derek Hale, an older werewolf who initially mentored Scott. In season 1, he was motivated by his revenge - hunting down the killer of his sister, while simultaneously showing Scott get acclimated with his new nature. Things between the two werewolves began to change in season 2 when Derek became an Alpha. Much of their disagreements stemmed from Derek's more aggressive and questionable ways. Despite this, he remained an ally, joining Scott and his pack in their endeavors.
As a core cast member - alongside Posey and Dylan O'Brien, who played Stiles Stilinski, Hoechlin's decision to leave Teen Wolf ahead of season 5 was a big blow to the show. Fans were dismayed, especially considering that by that point, the series had already suffered a string of character losses. However, unlike other instances where characters were written out of the show, Hoechlin's exit was entirely his decision. Acknowledging that Derek was no longer the main narrative player that he once was, the actor opted to look for other opportunities rather than be stuck as a background character in Teen Wolf.
It was the show's creator Jeff Davis who broke the news that Hoechlin wouldn't be back for Teen Wolf season 5. In an interview with Buzzfeed, he revealed that the actor wanted to "pursue movies." Despite his exit, Derek wasn't completely written out of the show; he was merely downgraded from a series regular to a recurring role, with Davis sharing that season 4 wouldn't be the last viewers will see him. Lo and behold, after missing the whole of season 5, Hoechlin and Derek returned for season 6 - just in time for the show's ending, which delighted a lot of the show's original viewers.
Hoechlin's provided reason for exiting Teen Wolf checks out as he appeared in a string of films after he shed his werewolf role. Since leaving he starred in Everybody Wants Some!! and Undrafted, both released in 2016. He also appeared in Stratton (2017); Fifty Shades Freed (2018); The Domestics (2018); Bigger (2018); Then Came You (2018); Can You Keep A Secret (2019); and most recently Palm Springs. Despite that, Hoechlin is still mostly focused on TV work, especially after he's cast as The CW/Arrowverse's Clark Kent/Superman. He's reprised the role several times now, appearing in various shows in that DC small screen franchise. Next year, Hoechlin will spearhead his own series titled Superman & Lois alongside Bitsie Tulloch.