I have two favorites for different reasons, though I’ll only write on one today. I chose the first because of his attitude and characterization (Hikaru Tezuka from Toshokan Sensou). I chose the second because of his history. I think that this second character may be considered a main character due to his extensive involvement in the series, but since the main focus isn’t usually him, I’ll consider him a side character for the purposes of answering this question, and I’ll choose him for the prompt. Yuri from Planetes is a glorious character.
Yuri and his wife are traveling in space. His wife, nervous, wears an engraved good-luck charm around her neck. What’s written inside the compass lid, wonders Yuri. Ah, but every married couple should have a secret or two, insists his wife.
Yuri gets up to get some coffee in another part of the space plane. Where are you going, worries his wife. Don’t worry, I’m not leaving you, assures her husband.
She looks out the window. What is that speck of light? And then…it happens.
Yuri looses his wife in a space-travel accident, and he’s become a debris hauler because he’s determined to find his late wife’s good-luck charm: a compass. For eight years the man searches, checking the disposal logs of other space companies on a weekly basis to make sure that someone else didn’t pick up this piece of his wife’s history and, eventually, he almost looses his life retrieving it.
As the episodes progress, we witness Yuri in a sort of revival process. He hasn’t forgotten his wife, but he’s becoming more alive in ways that his late wife would have wanted for him. Planetes is a show filled with philosophical questions, and Yuri’s journey of self is just as profound as any, if not quite as deeply touched upon.

What do you think of Planetes and of Yuri?
Who is your favorite male supporting anime character?
Shoujothoughts ❤