Teenager Kerim Frei wants to re-establish himself in the Fulham side after a disappointing campaign.
After an impressive breakthrough season, the 19-year-old winger featured on just eight occasions last term.
Niggling injuries and a loan spell at Cardiff limited his playing time at Craven Cottage and Frei wants to prove his worth to Martin Jol's side once again.
"On a personal level, I don't think it was a great season," the Turkey international told the club's official website.
"I had two injuries and that set me back - it was difficult to get back to the level that I wanted to be at. But every day I feel a lot better, sharper, stronger and quicker.
"It's unfortunate that we now have the break because all I want to do is play football and show what I can do again.
"My number one target is to break into the first team again and impress the manager and coaches over the summer months - I want to be in their plans for the new season."
The experienced goalkeeper spent the second half of last season with the Pirates on loan from Millwall and has signed for John Ward's men after his Lions' contract expired.
Chairman Nick Higgs told the club's official website: "We are delighted to have signed Steve as he really helped turn our season around last season.
"During his time with us he became a popular member of the squad, and worked hard to get us out of danger.
"I believe it is vitally important to have a permanent goalkeeper, rather then relying on loan signings, and I believe Steve will be part of a solid defence next season."
Mildenhall's two-year deal has the option of a third year triggered by appearances.
