
The centre-back has signed a three-year contract with the Pilgrims following his successful loan spell in 2025/26, which culminated in him winning the club's Player of the Season award.
Mitchell admitted Argyle was 'the only place' he wanted to be in the forthcoming campaign but had to be patient for that to eventually happen.
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The 24-year-old started pre-season at Charlton and while he trained with the first team squad he did not play in any games for them so his fitness levels will need topping up now that he has made a full-time move to Argyle.
The wait was worth it for Mitchell, though. He told Plymouth Live: "I do love being here, I haven't stopped smiling. Being at Argyle, I love the place. Off the pitch there is a lot of cool stuff.
"It's the only place I wanted to go. I just love living here, and this club last season was unbelievable. I know this season will probably be the same."
Mitchell's pleasure at being back at Home Park has been matched by the delight of the Green Army at his return. He said: "I was having breakfast the other morning and someone was shouting out of a car to me. It's top, unbelievable.
"I love it down here, I think it's filled with good people and very passionate people, and that's what you want to play for."
Amid reports that Wycombe Wanderers were also interested in signing Mitchell this summer, he began pre-season at Charlton as they prepared for their Championship campaign.
He said: "I'm grateful to Charlton because they could have just put me in the under-21s and forgotten about me but they kept me as fit as they could."
Mitchell was also helped out by Charlton's Plymouth-born former Argyle defender Lloyd Jones. "My mate Lloydy put me up where he lives in London for three weeks so I owe him a massive favour," he said. "I saved a lot of money on hotels and rent!"
Argyle's 1-0 win away to Truro City on Saturday saw Mitchell get his first run-out of pre-season as he played the first half of the match in Cornwall before being substituted.
He said: "It was top, but I was absolutely shattered though. It's the first minutes I have had. You have got to take positives from it - clean sheet, 1-0 win again. A 3,000 attendance so it was rammed..
"You could tell I was struggling a little bit. I was chasing my touch but it will get there. I think it will take me three, four, five games and I will be back to normal."
On what it will take for him to get up to full fitness, Mitchell said: "Playing and sleeping, and eating right. I was at the Steak and Omelette the other day and it was good but I probably need to stick off the crispy onions to be fair!"
After Mitchell's fine performances for Argyle last season, and the team's near miss of making the League One play-offs, there will be high expectations for 2026/27.
Mitchell said: "Hopefully I can replicate last season. It's going to be a tough league this year. I think if we just keep consistency we will be right up there."
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