Shop
The result, which revived the side's flagging hopes of qualifying for next season's Champions League, was secured with just 15 minutes remaining, as De Rossi arrived inside the penalty box to prod home a loose ball from close range.
The captain's ecstatic celebration underlined just how much it meant to both him and the side, as it snapped a three-match run without a win for the Giallorossi.
Claudio Ranieri's side are up to sixth in the Serie A standings - just a point behind fourth-placed AC Milan.
Perhaps it was not a sparkling Roma performance, but it was certainly a dogged, determined one. The away side stayed in the game and were eventually rewarded, as Patrik Schick's flick-on from a corner ended up falling kindly for De Rossi to be the hero.
Clear-cut chances were scarcer throughout the rest of the game, with Nicolo Zaniolo perhaps guilty of missing the best - while Patrik Schick also headed narrowly wide as he went up against his former club.
At the other end, Antonio Mirante was on hand to parry away a strong drive from Gregoire Defrel.
In the final 15 minutes Sampdoria pushed hard for an equaliser, but Ranieri's side resisted all threats to take a priceless three points.
Imperium Partners
Centurion Partners
