Semmler got his start casting Bloodline Champions and eventually traveled to Sweden to be part of the GD Studio. Following a stint casting StarCraft II, he transitioned into casting CS:GO alongside Anders Blume for Ninjas in Pyjamas' channel, NIPGamingTV, and the two quickly made a name for themselves as the most prominent Counter-Strike casters.
In 2014, he and Anders departed NIP to found Room On Fire, and in 2016, both cast their first Overwatch tournament at the Overwatch Open, which was co-presented by ELEAGUE and FACEIT.
In 2017, it was revealed that Blizzard had hired Semmler ahead of the inaugural Overwatch League season to cast Season 1 in Los Angeles. This meant that Semmler would not attend the 2018 ELEAGUE Major in Atlanta and Boston, which ran concurrently.
|2019-08-25||Premier||Overwatch League - 2019 Regular Season||Commentator|
|2018-09-09||Qualifier||Overwatch World Cup 2018 - Los Angeles Qualifier||Commentator|
|2018-08-26||Showm.||Overwatch League - Inaugural All-Star Weekend||Commentator|
|2018-07-28||Premier||Overwatch League - Inaugural Season Playoffs||Commentator|
|2018-06-17||Premier||Overwatch League - Inaugural Season||Commentator|
|About achievementsBroadcasts from any Tournament|
- 2018-01-26 | Semmler on his casting career and the Overwatch League: 'Casting Overwatch does feel like coming home in a way.' by Volamel of EsportsHeaven