The 1890–91 season was Sheffield United's second, and their first and only season playing in the newly formed Midland Counties League, as the club sought to establish itself as a major footballing force. The team was selected by the club's football committee and coached by a trainer, but day-to-day affairs were overseen by club secretary Joseph Wostinholm. The club saw a large influx of players during the season as it continued to bolster its numbers with amateurs loaned or signed from other teams in the local area, a policy that resulted in an unsettled side, indifferent league results, and a mid-table finish.