[9] His outstanding performances at the club led him to be loaned to Atlético's subsidiary, Athletic Bilbao, specifically for the 1909 Copa del Rey, where he played alongside the likes of Luis Saura del Pan, Julián Ruete, and André Didisheim as Bilbao were knocked out in the first round by Club Ciclista of San Sebastián.

[4][10] When he returned to his hometown, Vega de Seoane was elected as the third president of Real Sociedad in 1915, a position that he held for two years until 1917, when he was replaced by Xabier Peña, but then served a second mandate between 1924 and 1927, when he already was the mayor of San Sebastián.

[5] As a Mining Engineer, Vega de Seoane practiced his profession in countless Spanish exploitations, and was also in charge of the Gipuzkoa fishing owners, creating various modern industries in Pasaia.

[13] He resigned a few months after exercising his mandate, dissatisfied with the government of Primo de Rivera, but in the following years, he continued to be connected with municipal politics.

[6] His mortal remains were buried in the Poblenou Cemetery and the funeral ceremonies were held in the parish church of Santa María, constituted two major stages of mourning.