The Dutchman had an impressive campaign at Hillsborough in 2015-16 before succumbing to injury, but has now agreed fresh terms with the Owls, still without a new head coach following the sacking of Stuart Gray.
On his deal, Loovens said on Twitter: “Looking forward to the new season. An exciting challenge ahead. Love you all #swfc - onwards and upwards. :-)”
His signing follows on from Portuguese midfielder Jose Semedo signing a one-year contract, with Kieran Lee having penned a two-year deal earlier this month.
Keeper Chris Kirkland is expected to follow suit and commit his future to the Owls, but fellow out-of-contract star Chris Maguire is the subject of interest from Bolton Wanderers.
Maguire has been in talks with the Trotters, who signed former Owls striker Gary Madine earlier this close season.
The 26-year-old has stalled on signing a new deal offered at Hillsborough, which is believed to be on reduced terms.
Swindon Town manager Mark Cooper remains in the Owls’ sights regarding the vacant head coaching position at the club, with former Sporting Lisbon and Besiktas manager Carlos Carvalhal lined up to be a director of football.
Wakefield-born Cooper, 46, whose deal at the County Ground is due to expire next summer, has been sounded out by the Owls.
The compensation wanted by Swindon viewed to be the only real stumbling block.
The Owls are believed to be waiting to formally announce Carvalhal’s arrival until they have appointed a head coach, with the club still hopeful of an announcement this week.