Alfaro, a Mexican native, started his professional career when he signed for the Seattle Sounders on Jan. 15, 2016. The 27-year-old made his debut for the Sounders in a 2-1 loss to the New England Revolution on May 29, 2016. In three seasons with the club, Alfaro made 31 appearances across all competitions with Seattle. During his tenure in Seattle, the center back also represented their United Soccer League (USL) affiliate, the Tacoma Defiance. Alfaro scored two goals and recorded an assist in 37 appearances.
Following his stint in MLS and USL, Alfaro joined Chivas Guadalajara in Liga MX (Mexico) on Jan. 1, 2019. Alfaro played in three matches for Chivas Guadalajara in the 2019 season before joining Club Atlético Zacatepec in the second division of Mexican soccer, on loan on July 1, 2019. In one season with Zacatepec, Alfaro made 14 appearances in league play before rejoining his parent club at the conclusion of his loan.
After the 2019 season, Alfaro left Mexico and joined Reno FC in the USL Championship on Jan. 31, 2020. In one season with Reno, Alfaro made 11 appearances.
Prior to his professional career, Alfaro spent five seasons at California State University, Dominguez Hills, in NCAA Division II. He scored 10 goals and recorded six assists in 75 appearances. Alfaro was selected in the second round (27th overall) by the Seattle Sounders in the 2016 MLS SuperDraft.