As of yet there is no definitive news on the fee paid or the contract length in relation to the deal, although transfermarkt suggest the Schwarzwald side have spent €1.2m.
Gulde could be the second Karlsruhe player to head for Freiburg, with Jonas Meffert expected to join on loan from Bayer Leverkusen - who bought him early this month.
A career yet to take flight
The defender is now at his third club in the Baden-Württemberg region, having previously spent time at TSG 1899 Hoffenheim along with his current and future teams.
Gulde began his career with the Sinsheim side as a very promising youngster, he won the Gold Fritz Walter Medal in 2008 for the under-17 category.
There was limited game time with Hoffenheim, however, and he moved on to SC Paderborn 07 in search of first-team football.
Game time is key
A one-season stay in Paderborn was followed by a switch to the Wildparkstadion, and regular time on the pitch.
Yet it wasn't until last season where Gulde showed why he was so highly regarded as a youngster.
He made 32 appearances and played in both legs of the relegation play-off. Despite his fine individual performances, Karlsuhe were undone in the final minutes by HSV.
This season also saw Gulde perform well but the team couldn't hit the heights of last season, though he will get his chance in the top tier once again.
Gulde, who was speaking to the club website, said: "We've been in contact for a long time and I had good discussions with the officials."
He added, "SC Freiburg is a down to earth club, in which you have to work hard and I connect with that. My goal is, of course, to play as many games as possible."