A hectic day of activity saw Gary Liddle arrive at Valley Parade as Nathan Doyle went the other way.
But it is the new three-year deal - plus captain's armband - for player of the year Darby that the club believe will signal their intent.
Parkinson said: "Stephen was terrific last season and it was a real priority of ours this summer to get his signature on a new contract.
"He is a tremendous professional on and off the pitch. He will be our captain and it is a big responsibility but it is one I know he is ready for."
Darby started every game last season - and only came off once late on at Port Vale. He also skippered the team twice in Gary Jones's absence.
Central midfielder Liddle has signed a one-year deal, with the option of a second believed to be based on appearances.
The 27-year-old was on Parkinson's target list during the 2012 revamp but had already agreed to join Notts County.
After 283 games in six years with Hartlepool, scoring 21 goals, Liddle played a further 87 times for the Magpies.
He played every minute of their 2013 campaign - equalling a club mark last set by Pedro Richards 30 years earlier - but missed a chunk of last season with an ankle injury.
Liddle, who can also operate as a centre half, still played 36 games and netted four times.
He said: "I'm delighted to have signed for a club with a proud history and one with huge ambition.
"Phil rang me pretty soon after the news got out that I was leaving Notts County and I was delighted to see his name flash up on my phone.
"Straight after my meeting with him, I spoke with my agent and my family to tell them that this was the manager I wanted to play for.
"Truth be told, there was a chance of me signing for Bradford a couple of years ago, so it's nice to see the manager still interested in me."
The capture of another central midfielder inevitably means the end for Doyle after 94 appearances in his second Valley Parade spell.
His partnership with Jones was the axis of the double assault on Wembley in 2013. Parkinson said: "We've decided to shake hands and part our separate ways."