*Club domestic league appearances and goals, correct as of 23:51, 15 April 2023 (UTC) ‡ National team caps and goals, correct as of 17:00, 13 November 2020 (UTC)
On 26 June 2015, Alario became River Plate's fourth signing of the season, joining the Buenos Aires-based club on a four-year contract for a fee of 2.25 million US Dollars.[6] He made his debut on 11 July, replacing Fernando Cavenaghi for the final 30 minutes of a 1–1 home draw against Temperley.[7] Eleven days later, as a substitute, he equalised for a 1–1 draw away to Paraguay's Club Guaraní in the second leg of the Copa Libertadores semi-finals, converting a pass from Tabaré Viúdez to send River through 3–1 on aggregate to their first such finals since 1996.[8] On 5 August, in the second leg of the final after a goalless first, he finished Leonel Vangioni's cross at the end of the first half to open the scoring as his team won 3–0 against Tigres UANL.[9]
Eighteen days after River won the continental championship, Alario was sent off in a 2–1 domestic loss to Estudiantes de La Plata.[10] His first league goals for the Millonarios came in the form of a hat-trick on 6 September, in a 4–1 win away to Nueva Chicago.[11] On 31 October, as a 55th-minute substitute for Nicolás Bertolo, he scored the only goal in a win at Vélez Sarsfield.[12]
On August 25, 2016, Alario scores again finishing the game and yet another international title with River Plate in Buenos Aires to take over Recopa Sudamericana 2016. He was rated by many football experts in Argentina as the best striker playing in Argentina.
Bayer Leverkusen
On 22 September 2017, Alario signed for German side Bayer Leverkusen on a five-year deal.[14]
Alario received his first international call-up for Argentina on 12 August 2016, for matches against Uruguay and Venezuela.[17] Alario had his first appearance on 1 September 2016, coming from the bench replacing Lucas Pratto in the 71st minute during a World Cup Qualifier 2018 match against Uruguay.[18] He scored his first international goal when he netted the fifth in a 6–0 friendly win away to Singapore in June 2017.[19]
Alario was included in the Argentina squad for the 2021 Copa América, but withdrew due to a thigh injury and was replaced by Julián Álvarez.
^"Inter contrata atacante Lucas Alario" [Inter signs forward Lucas Alario] (in Brazilian Portuguese). SC Internacional. 4 January 2024. Retrieved 5 January 2024.