Romeo is one of the main characters, along with Juliet, in the play “Romeo and Juliet”. His role in the play is to function as a protagonist and tragic hero. As a tragic hero, Romeo falls in love with women too quickly and finds himself either in a state of severe depression or getting married to quickly. He suffers from a few tragic flaws – he rushes into things, does not think about his actions before he takes them, and ignores the advice of others. Due to these tragic flaws he suffers a tragic downfall at the end of the story when, due to the murder of Tyblat that he commited, is banished and taken away from his wife Juliet, and then kills himself when he thinks that Juliet has committed suicide. He is one of the characters who pushes the plot of the story along, a story that would not have been possible without this character.
By role, do you mean his purpose? On one level, he is simply one of the protagonists -- a key character whose choices play a major role in the conflict. By choosing love with the daughter of his enemy, his actions have a major impact on the play. By simply tracing his actions in every scene where he appears, you can give a plot-based answer to, "What is Romeo's role?"
Then there is a thematic answer. How do Romeo's actions show patterns and trends and get at key ideas explored in the play: love, fate and free will, identity, haste and moderation, youth and age?
Regarding love: Romeo draws major conclusions about love in act 1, scene 1, where he says
O brawling love! O loving hate!
O any thing, of nothing first create!(175)
O heavy lightness! serious vanity!
Misshapen chaos of well-seeming forms!
Feather of lead, bright smoke, cold fire, sick health!
Still-waking sleep, that is not what it is!
This love feel I, that feel no love in this.(180)
Through his use of oxymorons, Romeo communicates confusion and bitter disappointment with love, as Rosaline has rejected him, sworn to remain chaste. Since "heavy lightness" is an oxymoron, the pairing of two opposites that don't fit, it is one instance of how a character can show s/he is out of sorts and lost. If love is like "cold fire" and "sick health," that doesn't sound like much of relationship one would want. So, is Romeo's role to teach us about love...how one can move from a mistrust of love to embrace a true love?
When Romeo first sees Juliet in act 1, scene 5, he says this about love:
Did my heart love till now? Forswear it, sight!
For I ne'er saw true beauty till this night.
Romeo has fallen in love at first sight, and you may wish to analyze whether true love is possible at this stage. He swears his love is real now, based on "true beauty." Is there a truth here? Do his succeeding actions (the way he treats Juliet, the risks he takes for her, and any other actions you can track) demonstrate true love? Is Romeo here to teach us how a young man can discover true love?
You can choose lots of different themes to explore. The other one worth investigating is fate versus free will. Elizabethans struggled with a hierarchical world, seemingly driven by god, kings, and a calcified social strata, versus the reality of ever-changing daily life -- the growth of the merchant class, the rise of English political power, plagues that decimated the rich and allowed some poorer folks a chance to rise in terms of class, and other variables that made a person wonder whether fate drove his or her life or free will. Where in the play does Romeo talk about fate and choices? Look at the moments before the men crash the Capulet party: Romeo speaks to a dark dream he had about bad things happening, yet chooses to go on to the party anyway:
I fear, too early; for my mind misgives
Some consequence, yet hanging in the stars,
Shall bitterly begin his fearful date(115)
With this night's revels and expire the term
Of a despised life, clos'd in my breast,
By some vile forfeit of untimely death.
But He, that hath the steerage of my course,
Direct my sail! On, lusty gentlemen!
Examine this passage for an oxymoronic attitude toward fate (also called "stars" or "heavens" to represent supernatural power, providence). Be led by fate, or defy it? (In Act 5, Romeo yells that he defies the stars.)
This play is an adventure in analysis. See what you think Romeo's role is vis-a-vis these themes.