Colonel N. P. Hallowell, his first regimental commander, thus wrote of him:
With all who knew him, I mourn the loss of Alden. You knew him, and knowing him, need not be told how he discharged every duty, quietly, faithfully, cheerfully. It must have been high motives that led him, with his difficulty of hearing, and I think total disinclination to anything military, to leave his studies for this. . . . When he offered his services to aid the Fifty-fourth, as an officer, or in any other way, I tried very hard to dissuade him from taking the field, and finally was forced to refuse him my influence, on the ground that he lacked military experience. He was too much in earnest to give the project up. He applied himself to Casey's Tactics, and when the Fifty-fifth was started, again presented himself,—this time with credentials from his military instructor. He so clearly saw that a colored regiment was to be his field for labor, he was so religiously in earnest, that I no longer felt it right to stand in his way. His was the first commission issued in the Fifty-fifth, and his was the first life demanded.