Dolphins boss Tom Killick has persuaded the former Wales international to sign on for the ambitious Tatnam outfit.
Browning, who made more than 180 appearances for AFC Bournemouth from 2002 to 2007, was scheduled to feature in Poole's home Premier Division clash against Moneyfields on Saturday.
But the game was called off because of a waterlogged pitch, along with Poppies' visit to Brading.
Browning, who played for Bath City last season but has not featured for any club this term, is eligible for Dolphins' Wessex League Cup second round home tie against Fareham Town on Tuesday.
The 39-year-old won't be lining up at Tatnam, though, because of a prior commitment, so is likely to make his debut for Poole at Romsey in the league next weekend.
Browning may not end up being a permanent fixture for Dolphins, however.
Killick said: Marcus has a wealth of experience he could bring us.
He lives in Bournemouth and hasn't played for anyone this season and, at the moment, is not sure how much he wants to commit to us.
So he'll play a game or two, see how he feels about it and then decide whether he wants to pursue playing for us more.
Initially, it's just a matter of whether he wants to do it, but I will be keen for him to join us.
He's proven at a much higher grade and can be a great attribute for us.
Marcus was going to be involved on Saturday against Moneyfields so it's a pity the game was called off.
He can't play on Tuesday because he has a prior commitment he'd made before signing, so hopefully he'll be available for our game at Romsey.
Marcus does some coaching with the youth team at Cherries, so he has to make sure whatever he does fits in with that.
He can play in midfield and defence and would bring a further calmness and experienced attitude to our side.
Marcus has been a pro player for a long period. Bringing those sorts of players into the club can only be beneficial to our other players.
I'm not getting carried away with it yet. As much as I'd like Marcus to play a big role for us, it's something he's still considering rather than being fully committed to us.
Ex-Saints defender Phil Warner, who last played in Australia, can line up against Fareham tomorrow after Poole received international clearance to use him on a short-term basis.