The 35-year-old has been in charge of the first team since being promoted from his role as Under-23s coach when Alexander Nouri was sacked at the end of October.
Kohefeldt has been at the helm for just one game to date - the 2-1 defeat against Eintracht Frankfurt - and the Werder Bremen board were expected to bring in a new man as the side sits second-bottom in the table with no wins from 11 games and five points adrift of safety.
But it has now been confirmed that Kohfeldt will stay in charge until the end of the year.
Sporting director Frank Baumann said: "We are convinced that Florian should be given the chance to continue his work until at least the winter break. He has earned the opportunity because since he has come in, he has confirmed our positive opinion of him and his coaching methods.
"Florian was the benchmark in terms of our search for a new head coach. In our discussions, we were more convinced by him than any of the other candidates.
"Now it is all about fully focusing on the rest of the games before the winter break. We're confident that Florian can get us out of the relegation zone."