The 24-year-old put pen to paper on Saturday and was delighted to secure his future in Perth.
He said: "It's pretty exciting. It dragged on for a while, but I love it here in Perth. I have so many fond memories and I love the direction the team's going.
"I had a lot to weigh up with and away from football, but in my heart I always knew Western Australia was where I wanted to stay.
"I came over here to get an opportunity and those that I've been given by Mitch (coach John Mitchell) and RugbyWA have been fantastic, so I wanted to repay that.
"I feel I'm coming into my best football and didn't think locking in for a long period was what I needed at the moment.
"I wanted to set myself a challenge to become better in two years and that's what I hope to do."
Saturday proved to be a day of contrast for Shepherd. Just hours after he signed his new deal, the Force full-back endured a loss to the NSW Waratahs at Subiaco Oval.
The Waratahs' defence was brilliant all night and they deserved the 17-12 victory, but two incredible pieces of luck helped their cause and both involved Shepherd.
The first came when a penalty attempt from Shepherd hit the upright and crossbar before missing, and the second saw Lachie Turner score the game-sealing try after an attempted dribbled kick through the Force defence by Lote Tuqiri rebounded off Shepherd's boot and into the waiting arms of Turner.
"Unfortunately, we couldn't get the job done against the Waratahs, but it's the bounce of the ball that sometimes doesn't go your way. We just have to deal with that and move forward," Shepherd said.
"I keep going over what I could have done differently and it keeps going by in slow motion. It might play on my mind for a couple of days, but I just have to try to put it out of my head and hopefully next week I get that lucky bounce.
"That was one thing that put us on the back foot, but we had a chance to win the game.
"We pushed a few passes that we should have held onto, we are building momentum with a lot of phases and it's just that last play that is where we're lacking."
The Force's task of making the finals will now rely on them winning all of the remaining four games.