Fearns is Telford's second early post-season signing, following the arrival of Southport midfielder Liam Blakeman.
Meanwhile, Lee Vaughan, Asa Charlton and Carl Rodgers have all agreed new deals at Telford.
Smith said: "They were three of the easier ones. They were five-minute jobs really as they all wanted to stay."
Mattie Wood has been released, while young Elliott Dorrell has been signed for another year but told he will be sent out on loan to gain useful first-team experience.