Net earnings for the March quarter were US$161.2 million, down from $202.8 million a year earlier, while adjusted net earnings were $167.8 million.
Adjusted earnings per share were 63c, below Canaccord Genuity's estimate of 66c and below consensus of 67c.
"The slight miss was attributable to higher cash costs, depreciation, and taxes," Canaccord analyst Carey MacRury said.
Cashflow, including net cash provided by operating activities was $208.2 million, while free cashflow was $42.7 million.
EBITDA was $340.9 million.
Revenue was $551.8 million from the sale of 308,029 ounces of gold at an average price of $1788 an ounce.
Production of 302,847oz was above guidance of 270,000-290,000oz, while all-in sustaining costs of $846 an ounce was well below guidance of $1000/oz.
"We benefited from strong results in March, which was the key driver for higher than expected production and materially better than planned AISC in Q1 2021," Kirkland Lake CEO Tony Maluch said.
"We have had a solid start to 2021 and are poised for three strong quarters of operating results over the remainder of the year.
"Assuming current gold prices, we are also well positioned for improved financial performance beginning in the second quarter and expect to finish 2021, once again, as among the most profitable companies in our sector."
Capital expenditure for the quarter was $106.8 million, while exploration and evaluation expenditure was $42.4 million.
Cash at bank dropped to $792.2 million from $847.6 million after the return of $96.6 million to shareholders.
"The company is debt-free, and we forecast Kirkland achieving a net cash position of circa $1.3 billion by YE21 at spot gold," MacRury said.
MacRury maintained a buy rating and C$60 price target.
Kirkland Lake shares closed 1.9% higher at $48 in Toronto, while CDIs in Australia opened 1.2% higher at A$50.60.
