Portsmouth have signed striker Oliver Hawkins from Dagenham & Redbridge for an undisclosed fee.
Hawkins, who scored 18 goals in the National League last season, has signed a three-year contract at Fratton Park.
Pompey manager Kenny Jackett said: "We're really pleased to get Oliver over the line and I'm looking forward to working with him. He's someone I've watched for a long time and is capable of stepping out of non-league and doing well for us, complementing the players we've already got.
"He will obviously add some physicality to our squad. He holds the ball up and is a big threat in the box - in fact he's useful in both boxes."
Pompey boss Jackett has also brought in midfielder Stuart O'Keefe.
The 26-year-old former Crystal Palace player has arrived on a season-long loan from Cardiff.
Jackett told the club's official website: "We're very pleased to bring Stuart in for the rest of the season.
"He brings experience and aggression into our midfield and will complement the young ball-playing guys in that area of the pitch."
Pompey made it a hat-trick of deadline-day signings with the capture of Burton left-back Damien McCrory.
The 27-year-old will remain with Jackett's side until January.
Jackett told the club's official website: "He's an experienced player who provides competition for Brandon Haunstrup in that role.
"He's won promotion from this division before and has also played in the Championship, so we're delighted to bring him in on loan."
Portsmouth had time to land a fourth signing before the deadline, bringing in Cardiff winger Matty Kennedy.
The Scottish winger has arrived at the League One outfit on a season-long loan.