The DS Virgin Racing star finished clear of reigning champion Lucas di Grassi and third-placed Andre Lotterer to take the checkered flag in the Eternal City, getting its first taste of supercharged action.
The 31-year-old Briton claimed back-to-back wins in the first ePrix in New York last year and took the second of his seven career victories at the inaugural race in his home city of London in 2015.
His latest triumph in an eventful race on a 2.8 kilometer circuit in the Italian capital, came after pole sitter and fellow title contender Felix Rosenqvist of Sweden was forced to retire after making a mistake under pressure from Bird.
Mahindra Racing's Rosenqvist clipped a kerb while be chased by the eventual winner and damaged his suspension.
" In all honesty if he hadn't made a mistake he would have won the race," admitted Bird.
"We didn't quite have the race pace, but we hung on in there," he added.
Bird has closed within 18 points of Jean-Eric Vergne in the overall standings, with the title leader having to settle for fifth, two places adrift of his Techeetah teammate Lotterer, who charged through the field to claim a podium place for the second time.
There was heartbreak for Mitch Evans (Jaguar Racing) as he finished back in ninth spot after depleting his power in a battle for the lead with Bird.
Brazil's di Grassi was one to take advantage, moving up to claim second after a disappointing season for his Audi Sport team.
"The car has been very fast every race, " said di Grassi,
"We have had so many reliability problems, but I think we can fight to win every race in the rest of the season, he added.
However, di Grassi did end the race under investigation for his car swap procedure to the pre-race pitstop.
His teammate Daniel Abt of Germany set the fastest lap on the way to finishing fourth.
The thrilling race proved a fitting finale to Formula E's debut in Rome, a week initially marked by the visit Thursday of several teams and their personnel to the Vatican City for a private Apostolic Blessing by Pope Francis.
Race day also saw the appearance of several celebrities, including Hollywood actress Sienna Miller, with royalty represented by Prince Albert II of Monaco and the Duchess of York, Sarah Ferguson
Rome was round seven of the 12-race series, culminating in a double header in New York in July where Bird will be looking to emulate his earlier achievements and press his claim for a first Formula E title.