Revenue of $1.025 billion was up 11% from last year.
The strengthening in our markets that began mid last year accelerated in the quarter, and despite a wide variety of supply chain challenges, we responded to the increase and delivered revenue that was up 15% from the fourth quarter.
Geographically Asia, at plus 30%, drove much of the year-on-year growth.
Despite the inefficiencies and cost pressures, we were able to ramp up to meet the increased demand, and in the process of doing so, deliver record earnings per share of $1.38 and EBITDA margins just shy of 20%.
We delivered strong year-on-year growth in renewable energy of over 30%, while continuing to advance our announced $75 million investment plan.
We are now estimating full year revenue to be up 18% over last year, to a record $4.1 billion.
On the bottom line, we are guiding to a record $5.30 of earnings per share at the midpoint, which would be almost 30% higher than last year and 15% higher than 2019's record of $4.60.
And we remain committed to our long-term target of 20%.
Revenue for the first quarter was a record $1.03 billion, up 11% from last year and up 15% sequentially from the fourth quarter.
We delivered an adjusted EBITDA margin of 19.9%, up 70 basis points from last year's strong first quarter.
We also delivered record adjusted earnings per share of $1.38, up 24% from last year.
Organically, sales were up 7.5%.
Currency added 2.7% to the top line in the quarter, while the Aurora Bearing acquisition contributed just under 1%.
In Asia, we delivered strong growth again in the quarter, up 30%.
In Latin America, we were up 25%, led by higher revenue in distribution in the on-highway auto and truck sectors.
In Europe, we were up 6% as growth returned in several sectors, led by off-highway and distribution.
Adjusted EBITDA was $204 million or 19.9% of sales in the first quarter, compared to $177 million or 19.2% of sales last year.
This represents an incremental margin of roughly 26% all in, or 33% on an organic basis.
Currency had a slight positive impact on EBITDA in the quarter, and Aurora Bearing contributed about $1 million, with margins running ahead of our expectations.
On slide 13, you'll see that we posted net income of $113 million, or $1.47 per diluted share for the quarter on a GAAP basis.
This includes $0.09 of net income from special items, driven by discrete tax benefits in the period.
On an adjusted basis, we earned $1.38 per share, up 24% from last year and a new quarterly record for the company.
Our first quarter adjusted tax rate was 25.5%, in line with our expectations and slightly lower than last year.
For the first quarter, Process Industries sales were $521 million, up 14% from last year.
Organically, sales were up nearly 10%, driven by strong growth in renewable energy, distribution and general industrial sectors, offset partially by lower marine revenue.
The favorable impact of currency translation added roughly 3.5% to the top line in the quarter, while the impact of the Aurora Bearing acquisition added nearly 1%.
Process Industries' adjusted EBITDA in the first quarter was $136 million or 26% of sales, compared to $112 million or 24.4% of sales last year, with margins up 160 basis points.
In the first quarter, Mobile Industries sales were $505 million, up about 8% from last year.
Organically, sales increased 5.2%, reflecting higher revenue in the off-highway, heavy-truck and automotive sectors, offset partially by lower shipments in rail and aerospace.
Currency translation added 2% to the top line in the quarter, while Aurora Bearing contributed nearly 1%.
Mobile Industries' adjusted EBITDA for the first quarter was $80 million or 15.9% of sales compared to $76 million or 16.3% of sales last year.
You'll see we generated operating cash flow of $32 million in the first quarter.
After capex spending of $29 million, free cash flow was $2 million in the period, which was in line with our expectations.
From a capital allocation standpoint, in the first quarter, we returned $50 million to shareholders, with the payment of our 395th consecutive quarterly dividend and the repurchase of 350,000 shares of company stock.
Our leverage, as measured by net debt to adjusted EBITDA, was 1.9 times at March 31, unchanged from the end of 2020.
We now expect sales to be up around 18% in total at the midpoint of our guidance versus 2020, which is up from our prior outlook of 12% growth.
Organically, we're now planning for sales to be up around 15% at the midpoint, up from the previous outlook of 9% growth.
Currency is still expected to contribute about 2% to the top line, while Aurora Bearing is expected to contribute close to 1%.
On the bottom line, we now expect adjusted earnings per share in the range of $5.15 to $5.45 per share, which is also up from our prior outlook.
At the midpoint, our current outlook represents nearly 30% earnings growth versus last year.
For 2021, we now estimate that we'll generate free cash flow in the range of $325 million to $350 million, which represents just over 80% conversion on adjusted net income at the midpoint.
This assumes capex spending at around $150 million, or just over 3.5% of sales, which includes ongoing growth investments in areas like renewable energy.
For the full year, we anticipate net interest expense of around $60 million, and estimate that our adjusted tax rate will be about 25.5%, consistent with the first quarter, and both of which are unchanged from our prior outlook.

Summary:
Despite the inefficiencies and cost pressures, we were able to ramp up to meet the increased demand, and in the process of doing so, deliver record earnings per share of $1.38 and EBITDA margins just shy of 20%.
We are now estimating full year revenue to be up 18% over last year, to a record $4.1 billion.
On the bottom line, we are guiding to a record $5.30 of earnings per share at the midpoint, which would be almost 30% higher than last year and 15% higher than 2019's record of $4.60.
Revenue for the first quarter was a record $1.03 billion, up 11% from last year and up 15% sequentially from the fourth quarter.
We also delivered record adjusted earnings per share of $1.38, up 24% from last year.
On slide 13, you'll see that we posted net income of $113 million, or $1.47 per diluted share for the quarter on a GAAP basis.
On an adjusted basis, we earned $1.38 per share, up 24% from last year and a new quarterly record for the company.
We now expect sales to be up around 18% in total at the midpoint of our guidance versus 2020, which is up from our prior outlook of 12% growth.
On the bottom line, we now expect adjusted earnings per share in the range of $5.15 to $5.45 per share, which is also up from our prior outlook.