The attacker has signed a two-year deal with the League One outfit to bring an end to four years with Bromley.
I have always said Louis can play in the Football League, that is not in doubt, the question mark is how Kenny Jackett uses him.
Portsmouth must surely have seen how effective he is playing in the hole behind the front man during their various scouting trips.
He can also play off the striker and remains a player at his most damaging when picking up the ball and running at defenders.
Don’t get me wrong, he can be very effective on the right or left wings but they are roles which ensure he doesn’t get the ball as often.
In turn, that limits his ability to cause damage in more dangerous areas of the pitch. It has to be a number 10 role, for me.
Even if Louis doesn’t bring goals, he is going to bring something to the team.
Irrespective of whether he scores – and I am not convinced he is a 20-goal-a-season player – I have never seen a game when he doesn’t provide an opportunity for a team-mate.
Louis is always creating an opportunity for someone, which is reflected by 13 assists in addition to 22 goals in all competitions this season.
At his most dangerous he is quick but not lightning.
It’s more about how quickly he moves the ball rather than his pace off it.
It’s the trickery he brings with the ball at his feet, he’s able to get an extra yard on a defender if left in a one-v-one.
So many goals this season have come from drifting past players, all about the slalom run rather than beating just one man.
He can create something out of nothing.
We actually expected Louis to get back into the Football League quicker than he has.
At the start of Bromley’s 2015-16 National League season they were fourth in the early part of November and everyone was talking about him, scouts hovered.
Then he broke down at Christmas and was pretty much out injured for the remainder of the campaign.
We had expected to lose him during that January transfer window and, speaking to him, he knew of offers and interested clubs. Then injury intervened.
For last season, Louis had another good start but injury hampered him, particularly the final three months.
This season, at the age of 25, was going to be his make-or-break and he stayed fit for the entire duration.
And for any Pompey fans questioning whether he can do it at that level – just look at Jamal Lowe.