Eastwood became a regular fixture in the club's reserve team, helping them to the North East Lancashire Combination title in 1921.
He made his Football League Third Division North debut for Nelson on 1 October 1921 in the 1–1 draw with Darlington at Seedhill.
Eastwood played his final competitive match for the club in the 3–0 win at home to Walsall on 28 April 1923, after the team's Third Division North championship had already been confirmed.
Eastwood transferred to Morecambe in July 1923 and enjoyed a regular first-team berth at Christie Park over the following five seasons.
Eastwood missed a large portion of the 1928–29 campaign through injury, and left the club in the summer of 1929 to join Clitheroe.