Scottish winger Sinclair was signed by manager Matt Gillies for Leicester City in May 1965, for a fee of £25,000. Along with centre-forward Derek Dougan and (later in the season) Peter Rodrigues, Jackie was signed to help refresh the City squad which, since 1961, had reached two FA Cup Finals, played in Europe, come close to winning the 1963 league title, and had reached two League Cup Finals, winning one of them.
He came to Leicester from Dunfermline Athletic. In the season before Jackie’s move to Filbert Street, and under the guidance of the ex-Leicester City Northern
Ireland international Willie Cunningham, Jackie had starred in the Dunfermline side which came within a point of winning the league and then narrowly lost the Scottish FA Cup Final.
His impact at Filbert Street was immediate. Jackie scored on his debut in the first game of the season against Liverpool. He played in every game as a winger that season and was the Club’s top scorer with 24 league and cup goals.
He had great pace, mesmeric footwork, was a great crosser of the ball, was adept at cutting inside and formed a great striking partnership with Dougan. His efforts were rewarded with a Scotland cap against Portugal at the end of the season.
In his second season, continuing to play in a forward line which, for the most part, comprised Sinclair, Jimmy Goodfellow, Dougan, Davie Gibson and Mike Stringfellow, Jackie missed only one game and was once again the Club’s top scorer, this time with 22 goals.
In his third season at Filbert Street, Jackie was an ever-present, until December when he was surprisingly sold to Newcastle United for a fee of £67,500. This dismayed the fans, who had already seen the departures of Gordon Banks and Dougan towards the end of the previous season.
In his two and a half seasons at Leicester, Jackie scored 50 goals in 103 top flight games and another three goals in cup competitions. Averaging nearly a goal every two games was a remarkable achievement for a winger.
At Newcastle United, he won the UEFA Fairs Cup in 1969. He then moved to Sheffield Wednesday, before returning to Scotland to play for Dunfermline Athletic again prior to ending his career at Stenhousemuir. His cousin, Tommy Wright, played for Leicester City between 1989 and 1992.
Jackie sadly died after a battle with cancer in September 2010.