Shakespeare's characterization of Othello as a dignified, noble, and heroic figure is especially seen in other characters' descriptions of him as well as his own account of himself in his speeches.
For example, even though Othello has just committed a questionable act through marrying Desdemona without permission from her father, other characters are still willing to see him as blameless and noble. They are more concerned about needing Othello to handle the imminent attack from the Ottomites at Cyprus. When it becomes obvious that Desdemona truly loves him, they forget the matter of Senator Brabantio's objection to the marriage all together. The other characters' admiration of Othello is evident in their praise of him. For example, the Duke of Venice addresses Othello as "[v]aliant Othello" (I.iii.54).
However, Othello is characterized as a noble, valiant figure through even his own account of himself. For example, when Iago first warns Othello that Brabantio will be livid over the marriage, Othello reminds him of his services to Brabantio, saying "My services, which I have done the signiory, / Shall out-tongue his complaints" (I.ii.20). In addition, while Othello is waiting for Desdemona to be brought to the duke to give her own testimony about her feelings for Othello, he relays all the things he told Desdemona about his war history that made her fall in love with him, such as his escapes from death and even being sold into slavery, as we see in his lines:
Wherein I spake of most disastrous chances,
Of hairbreadth 'scapes i' the imminent deadly breach,
Of being taken by the insolent foe,
And sold to slavery, of my redemption thence. (I.iii.146-50)
Hence, we see that it is due to his bravery and perseverance that she falls in love with him. It is also his own account of his bravery and perseverance that makes the audience see him as a noble, valiant, dignified figure.
Othello's honor and nobleness is even restored to a point through his genuine repentance at having been deceived into committing a foul act. As he declares to Lodovico, Lodovico must speak of him as "one that loved not wisely but too well" and as one who was not easily made jealous, but rather as one who was deceived (V.ii.393-95).