Early years Nelson was born in
Greenock, Scotland, the sixth son of Alexander Nelson and his wife Jeanie. He started his football career there with junior sides St Paul's and Glenarm, initially playing as a forward. His spell with the team was disrupted by a broken leg during his second season, He was spotted by
Fred Stewart, manager of Welsh side
Cardiff City, who paid £500 to complete a transfer to Cardiff. Such was Nelson's success at Cardiff that the Welsh side sent a message to Crusaders asking "Have you any more players like Jimmy?". This correspondence ultimately led to
Tom Sloan and
Tom Watson also moving to Cardiff in the following years.
Cardiff City Nelson moved to Wales in 1921 when signed by Cardiff City, coinciding with the team being promoted to the
First Division of the
Football League. He made his debut for the club two months into the
1921–22 season, replacing captain
Charlie Brittain in a 2–0 victory over
West Bromwich Albion on 29 October. He retained his place for Cardiff's following match, a 2–0 defeat to
Manchester City on 5 November, but these proved to be the only senior appearances in his first season. The following year, Nelson again started the campaign as a reserve, with Brittain and
Jack Page being preferred in Nelson's favoured position. He made only one appearance during the first half of the season, but was recalled for a goalless draw with
Bolton Wanderers on 30 December 1922. Nelson retained his place for the rest of the season, missing only 4 of the remaining 19 matches and finishing the campaign with 24 appearances in all competitions. This included helping the side to victory in the
Welsh Cup by defeating
Aberdare Athletic 3–2 in the final. In the
1925–26 season he remained prominent in the first team and scored his first goals for the club, converting
penalties during victories over
Burnley and
Nottingham Forest in the second half of the campaign. The season culminated with Nelson and Cardiff both reaching their first
FA Cup final, losing
1–0 to
Sheffield United at
Wembley Stadium. In the opening game of the
1925–26 season, a 3–2 defeat to
Manchester City, Nelson became the first Cardiff player to be sent off in a Football League match. With the match tied at 2–2, Nelson became involved in an altercation with an opposition player in his penalty area. He was subsequently dismissed after the referee witnessed him kick opposition forward
Tommy Johnson, with Manchester City converting the resulting penalty to win the game. Nelson was later banned for a month following the clash and missed five league matches. Nelson missed the opening four matches of the
1926–27 season before returning to the side and remaining ever present for the remainder of the campaign, appearing in 50 consecutive games as Cardiff finished 14th in the First Division. At the end of the season, he helped the side reach the
1927 FA Cup Final against
Arsenal, shortly before which the
Daily Herald described him as "one of the best backs in the country". He also claimed his second Welsh Cup title as Cardiff defeated
Rhyl 2–0 in the final. However, this proved to be Nelson's last prominent season with the club. After featuring in the opening nine games the following campaign, he succumbed to injury and appeared only two more times as Cardiff suffered relegation to the
Second Division after finishing last. Nelson did not return to the first team on a regular basis until midway through the
1929–30 season. He won a fourth Welsh Cup title during his final season, scoring his last goal for the club in a 4–0 victory over
Swansea City, their
local rivals, in the sixth round.
Newcastle United Nelson left Cardiff in July 1930, signing for
Newcastle United for £7,000. He made his debut for the club on the opening day of the
1930–31 season in a 2–1 defeat against
Sheffield Wednesday. After one further appearance, Nelson was absent from the first team for three months before returning in November. He finished his debut season having made 25 appearances in all competitions. Nelson was still held in high esteem in South Wales from his spell with Cardiff and a benefit night was hosted in his honour in
Ystrad Mynach shortly after the cup final. As well as raising money for the
Caerphilly District Miners Hospital, Nelson was presented with a painting of himself and other items. He remained a regular for two further seasons, making 40 league appearances in both. A potential return to Cardiff was considered, with the side having fallen into the
Third Division South, while
Watford also showed interest in his signing.
Southend United Nelson joined
Third Division South side
Southend United in June 1935. Within the first six months, he helped the side win the Southend Hospital Cup, a regional competition. Nelson attended the award ceremony with his teammates in January 1936, during which his car was stolen from outside the venue before being abandoned in
Pitsea. He remained with the club until 1939, making 81 appearances in all competitions. losing out to
Billy Birrell. ==International career==