Sarll - who replaces outgoing boss Kevin Phillips - has been out of work since leaving National League Woking in November.
The Pools ended their first season back in the National League in 12th, 11 points away from the play-off places.
Sarll has experience with the play-offs having led both Yeovil Town and Woking to a top seven finish in previous roles, leading the Cards to their first-ever play-off campaign.
The 41-year-old boss has made dragging the Pools into top-seven contention next season his main priority.
He said: "I'm really excited to get started - the opportunity and challenge at the club is one I'm very much looking forward to. I'm coming here in order to win and we need to close that gap to the play-offs.
"We won't accept mediocrity, we need to challenge every season and that all starts from the dressing room. I can’t wait to start, creating a strong dressing room is the priority ahead of this pre-season.
"Over the years I have managed visiting teams at the Suit Direct Stadium and I am fully aware of the amazing passion the fans have for the club. The intensity they bring gives us a huge advantage and we must capitalise on this community's passion.
"I really want to create some lasting memories and be part of what is already an illustrious history. Supporters being proud of their town and team means everything to me."