Preheat your oven to 400°F and line a large baking sheet with parchment paper for easy cleanup.
Peel and cut the sweet potato into 1-inch wedges and trim the tough, woody ends off the asparagus spears.
Finely mince the garlic clove and strip the rosemary leaves from the stem, chopping them finely.
In a small mixing bowl, whisk together the olive oil, lemon juice, lemon zest, minced garlic, chopped rosemary, sea salt, and black pepper.
Place the chicken breast, sweet potato wedges, and asparagus on the prepared baking sheet in a single layer.
Drizzle the lemon-herb oil mixture over the chicken and vegetables, using your hands or a brush to ensure everything is evenly coated.
Roast in the center of the oven for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the sweet potatoes are fork-tender.
Remove from the oven and let the chicken rest for 5 minutes before slicing it against the grain and serving alongside the roasted vegetables.