The former Young Socceroo has transferred from Scottish First Division side Airdie United and previously spent time with Sheffield United.
 
Warren, who has supported Sydney FC since the beginning of the A-League, said he was excited to return to Sydney and looked forward to linking up with his team-mates.
 
"It's a great feeling coming home," Warren said. "I've always wanted to come and play for my home team, and after spending a couple of years overseas I thought it was time to come back.
 
"I still remember coming to the games when Dwight Yorke was here and I know a couple of the players so I'm happy to come back."
 
Sydney FC coach Frank Farina said the combination of Warren's time in Europe along with the ‘local boy' factor made him a perfect fit for the Sky Blues' setup in 2013/14.
 
"He fits into what we are trying to do and has had two years in Europe so has a bit of experience. Marc's a local lad too which is part of the culture we are trying to build here," Farina said.
 
• Meanwhile Wellington Phoenix have terminated the contract of Solomon Islands striker Benjamin Totori after the two parties reached a mutual agreement.
 
Totori had one year remaining on a two-year deal but new coach Ernie Merrick could not guarantee the forward regular time on the pitch next season.
 
The 27-year-old made 15 appearances in his only season with the Phoenix, failing to score a goal in that time.
 
The Phoenix's general manager David Dome said that the club had arranged for Totori to join Victorian Premier League side Oakleigh Chargers for the remainder of their season.
 
"That will give Benji more exposure and we may also look at bringing him back to New Zealand through our feeder club Team Wellington for the 2013-14 ASB Championship season," Dome said.
 
"We thank Benji for his contribution to the club and wish him all the best for the future."