The company posted record net earnings of US$110.1 million, up 120% over the March 2018 quarter, and adjusted net earnings of $112.1 million, up 114%.
EBITDA of $201.6 million and free cashflow of $93.1 million was also a record, and up 101% and 85% respectively year-on-year.
Revenue rose 54% to $304.9 million on a 57% rise in gold production to 231,879 ounces and a 33% improvement in all-in sustaining costs to $560 an ounce.
The strong result saw Kirkland Lake's cash on hand jump by 25% to $416.1 million and its quarterly dividend lifted by 34% to 4c due to a change in the currency of dividends paid from Canadian dollars to US.
Kirkland Lake president and CEO Tony Makuch said the company was off to a strong start in 2019.
"Our operating earnings were very strong and our net earnings beat the previous record in Q4 2018 even though we had unfavourable foreign exchange movements this quarter as well as a higher effective tax rate," he said.
"Looking ahead, with production and sales levels expected to increase in the second half of the year, we are well positioned for increased levels of profitability and cash flow going forward, assuming existing business plans and gold prices."
Both of Kirkland Lake's flagship mines, Fosterville in Victoria and Macassa in Ontario, had record quarters, producing 128,445oz and 72,776oz of gold respectively.
Makuch said the company was confident it would continue to see very strong results from Macassa for the remainder of the year.
"At Fosterville, we continued to develop on, and increase production from, the Swan Zone in Q1 2019, with stope production advancing on multiple levels," he said.
"As we develop deeper into the zone, we are targeting higher levels of production from Swan, particularly in the second half of the year, which is expected to drive higher levels of consolidated production in the third and fourth quarters."
The strong outlook led Kirkland Lake to further increase 2019 guidance from the original 920,000-1 million ounces at operating cash costs of $300-320/oz.
"Based on the strong results at Macassa and Fosterville in Q1 2019 and the outlook for the remainder of the year, we have raised the lower end of our consolidated production guidance for the year, and now expect to produce at least 950,000oz, and improved our operating cash cost per ounce sold guidance, which we are now targeting at $285-305," Makuch said.
Fosterville is now expected to produce 570,000-610,000oz, up from 550,000-610,000oz, at operating cash costs of $130-150/oz from $170-190/oz.
Macassa's guidance was refined to 240,000-250,000oz from 230,000-240,000oz, at operating cash costs of $400-420/oz from $440-460/oz previously.
Kirkland Lake held its annual general meeting in Toronto overnight, where director Jeff Parr was confirmed as chairman, replacing major shareholder Eric Sprott.
Kirkland Lake shares rose 6.3% in Toronto overnight to C$44.17, valuing the company at $9.29 billion. Its Australian depositary receipts were up 4.5% to A$46.90.