Graydon, who played Premier Division football with Bohemians previously, has been plying his trade with both Bray Wanderers and most recently the midlanders for the past three years.
The Dubliner insists he's ready for the step-up to full-time football and is confident he can rise to the challenge.
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"I'm looking forward to getting going," he said. "It's a big club to be part of and obviously I'm looking forward to being a part of the team that's building here," said the former Ireland underage international. "It's nice to get into a footballing team. I will bring a lot of speed and directness and hopefully I can make an impact on the team.
"I can play on both sides, right or left wing. I'm just looking to bring a lot of energy. I'm a direct player so I like to get on the ball and get at players and hopefully make a difference and get an end product and a few assists and hopefully add on to the goal tally."
Derry's style of play and the club's lofty ambitions appealed to Graydon's own vision for his future and so he didn't need too much time to think about his decision.
"Ruaidhri contacted me and I was excited. Hearing a big club like Derry is interested and wanted you I was happy. So I was happy to get the deal done and over the line and now I just can't wait to get going.
"The club is building something special and I'm just happy to be a part of it. They have great ambitions and I'm just delighted he's brought me in."
Longford Town boss Gary Cronin, who also worked with Graydon at Bray, was influential in helping facilitate the move to Derry and he believes the player has a big future and will benefit from playing full-time football.
"I enjoyed my football at Longford," added Graydon. "Gaz (Cronin) is a great guy. He helped me a lot and helped me with the move here as well. I haven't got a bad word to say about the club, it's a great club and obviously it's a step up for me but I believe I'm ready and it's one I've been waiting for, for a long time."
The fact he's played alongside both Brian Maher and Brandon Kavanagh during his spell with the Seagulls, will make it a little easier to fit into the Derry team.
"They are two top lads to be fair. It's' nice to come into a team when there's familiar faces. It's just about getting into the team, getting to know the players and gelling together and hopefully I can be part of the success at the club."
It's an exciting time to join the club with Thursday's UEFA Europa Conference League first round qualifier against Riga FC around the corner and he's hoping to be a part of that experience.
"At Longford I was playing week in, week out so fitness is not a problem so hopefully I can come in and make a difference now. It's every player in the League of Ireland's dream to play in Europe and I've joined the club at the right time with Europe coming around the corner. It's a big challenge but a challenge I'm willing to take."
Thursday's match will be his first Brandywell experience as a home player and he can't wait to play in front of the Candy Stripes support.
"I've played at Brandywell when I was at Bohs a few years back but I haven't been up since. It's a great crowd, a great atmosphere and a great stadium to play in so I'm delighted to get the chance to play in front of the home fans and hopefully I get a warm welcome."