Tarrant departed for Fremantle ahead of the 2007 season after an at-times turbulent 161-game career with the Magpies, but Buckley has been impressed with his former teammate's demeanour since his return via the 2010 trade period.
"It's probably a bit too much to say that it's like chalk and cheese because people develop at different rates, but over the four years he had at Fremantle, his development as a person and his maturity as a man has really been exponential," Buckley told Melbourne radio station 3AW on Monday.
"He's a lot more comfortable in his own skin, he's fantastic around the place and he's prepared to talk to the younger blokes.
"If blokes do the wrong thing around the place, he pulls them up for the wrong behaviours. He's a 30-year-old man now, he plays football well and he's very strong.
"We know he's great one-on-one and he's got a wealth of experience, so he's a fantastic addition to our list."
Buckley, who will take over from Mick Malthouse as senior coach at the end of the 2011 season, will coach Collingwood in round one of the NAB Cup and is looking forward to seeing Tarrant in action along with fellow recruit Andrew Krakouer.
The former Richmond utility turned heads with his stunning four-goal display in last week's intra-club practice match and Buckley backed him to have an impact for the Pies early in the season.
"He's been fantastic for us. He's just turned 28 and he's a new recruit," he said of Krakouer's return to the AFL following a 16-month prison term.
"He plays the game very well. He's worked his way through high forward and midfield positions and really excelled in our intra-clubs in the last couple of weeks.
"He's copping a bit of media at the minute and he's in great form so he'll definitely get a run very early in the piece for us.
"He's put himself in a great position to take advantage of a second chance … he's definitely earned it."
Collingwood will play off against Carlton and Richmond in round one of the NAB Cup at Etihad Stadium on Saturday night.
