The Vanarama National League North side made a change on Tuesday, the former Wrexham manager leaving the role he has held since 2014.
Mid-table Tamworth drew with York City on Saturday but it wasn’t enough to keep the 43-year-old at the club.
Now, Morrell has given more background to his time at the club and says he is proud of what he achieved.
He said: "As disappointed as I am to be leaving my role as manager at Tamworth FC, I am immensely proud of the progression the club has made over the past four seasons.
"During my tenure, the club has gone from a team of 20 players that were sitting third from bottom, to what is now, a thriving community club which has had two sevenths and a ninth-place finish in an increasingly competitive league.
"The club now runs an ever-improving Development Academy, a successful Scholarship programme and a triple winning under-21s, encompassing more than 220 local footballers under the Tamworth banner."
"We have helped oversee the introduction of a state-of-the-art 3G pitch and implementation of community projects and fun days.
"I leave with a 47 per cent win ratio and some fantastic memories, such as the 12-game winning streak during my first campaign."
He continued: "None of the above would have been possible without the tremendous support from many people and I have to give a massive thank you to Mike Fowler, George Delves, Claus Jorgensen, Kieran Berry, Lee Evans, Buster Belford, Degsy Bond and the rest of the medical department who have backed me and worked tirelessly to make the club a success.
"The volunteers, who know who they are, who live for the club and do anything they can to help, have also been incredible.
"And last, but certainly not least, my best wishes to the fans who have supported me through the good times and the bad. I wish the club all the success in the future."