Nicknamed El Pelado ("bald one") despite his traditionally long hair,[2] he played as a defensive midfielder and spent most of his career at River Plate and in Italy, representing four teams in the latter country.

Shortly after, he moved to Sevilla in Spain, for a record fee for a player in the country of $9 million;[3] he appeared regularly in his first and only season with the Andalusians, but suffered La Liga relegation.

He spent three seasons in Rome with Lazio, becoming a firm fan favourite especially after scoring a 35-yard goal against Parma's Gianluigi Buffon, his only of the 1999–2000 campaign, which ended with league and Coppa Italia conquest.

[9] The following year, after the team's relegation as second from bottom, he returned to Argentina and agreed to play for Quilmes, which appeared at the Libertadores, announcing his retirement after their elimination from that tournament.

[13] On 19 August 2009, veteran Almeyda finally re-joined his main club River Plate, teaming up with former teammates Marcelo Gallardo and Ariel Ortega.

[16] Almeyda spent 18 months in charge at River Plate, winning the Primera B Nacional and earning promotion back to the top division at the end of the 2011–12 season.

[28] After placing third overall in the Clausura's general table, the final second leg was played at the Estadio Chivas on 28 May 2017 and the hosts won their 12th title in the competition after besting Tigres UANL by an aggregate of 4–3; thus, they became the first team in Mexican history to win the double in a single season on two occasions.

[34] The following campaign, Almeyda's side managed to reach the playoffs, facing Sporting Kansas City in the first round but losing following a 3–0 penalty shoot-out after a 3–3 tie.

A tenacious, dynamic and physically strong player in spite of his diminutive stature, Almeyda excelled in a midfield holding role due to his stamina, tactical awareness, reactions, anticipation and work rate, as well as his ability to press opponents and break down opposition plays which allowed him to protect his team's back-line.

Due to his diminutive stature, tackling, and ability to cover a lot of ground during matches, Almeyda was given the nickname el tractorito ("the little tractor," in Spanish) in the media.