social events and celebrations and the return-to-office trending higher. During the first quarter of 2022, we remained focused on maximizing the vertical opportunity between the Famous Footwear and Brand Portfolio segments, with LifeStride, Dr. Scholl’s and Blowfish Malibu representing three of our top 15 best-selling brands during the quarter.
Gross Profit
Gross profit increased $52.1 million, or 19.0%, to $327.0 million for the first quarter of 2022, compared to $274.9 million for the first quarter of 2021, reflecting higher net sales and a higher gross profit rate. As a percentage of net sales, gross profit increased to 44.5% for the first quarter of 2022, compared to 43.0% for the first quarter of 2021, as strong consumer demand enabled more full-price selling and minimal promotional activity. The greater sales mix of higher margin brands and product categories within our Brand Portfolio segment also contributed to the gross margin improvement.
We classify certain warehousing, distribution, sourcing and other inventory procurement costs in selling and administrative expenses. Accordingly, our gross profit and selling and administrative expense rates, as a percentage of net sales, may not be comparable to other companies.
Selling and Administrative Expenses
Selling and administrative expenses increased $17.3 million, or 7.1%, to $260.8 million for the first quarter of 2022, compared to $243.5 million for the first quarter of 2021. The increase primarily reflects higher salary and benefits expenses and cash and stock-based incentive compensation plan expenses driven by our strong financial results in the quarter as well as our expectations for the full year. Our marketing expenses also increased as a result of tailoring our e-commerce marketing to the individual consumer in an effort to drive repeat purchases. As a percentage of net sales, selling and administrative expenses decreased to 35.5% for the first quarter of 2022, from 38.1% for the first quarter of 2021, reflecting better leveraging of expenses over higher net sales.
Restructuring and Other Special Charges, Net
We incurred restructuring and other special charges of $13.5 million ($11.9 million on an after-tax basis, or $0.31 per diluted share) during the first quarter of 2021, reflecting expenses associated with the strategic realignment of the Naturalizer retail store operations. Refer to Note 5 to the condensed consolidated financial statements for further discussion of these charges.
Operating Earnings
Operating earnings increased $48.3 million to $66.2 million for the first quarter of 2022, compared to $17.9 million for the first quarter of 2021, primarily reflecting higher net sales and gross profit. As a percentage of net sales, operating earnings were 9.0% for the first quarter of 2022, compared to 2.8% for the first quarter of 2021.
Interest Expense, Net
Interest expense, net decreased $9.5 million, or 80.5%, to $2.3 million for the first quarter of 2022, compared to $11.8 million for the first quarter of 2021, primarily due to the non-recurrence of the $6.4 million fair value adjustment to the Blowfish Malibu mandatory purchase obligation in the first quarter of 2021. The purchase obligation was settled for $54.6 million on November 4, 2021. In addition, we redeemed our $200 million aggregate principal of senior notes in the second half of 2021. By retiring our senior notes, we shifted our higher-rate debt to the lower-rate borrowings under our revolving credit agreement, which reduced our interest expense by approximately $3.1 million compared to the first quarter of 2021. These decreases were partially offset by an increase in interest expense attributable to higher average borrowings under our revolving credit agreement.
Other Income, Net
Other income, net decreased $0.4 million, or 10.6%, to $3.4 million for the first quarter of 2022, compared to $3.8 million for the first quarter of 2021, which reflects a reduction of certain components of net periodic benefit income. Refer to Note 13 of the condensed consolidated financial statements for further detail regarding the components of net periodic benefit income.
Income Tax Provision
Our effective tax rate can vary considerably from period to period, depending on a number of factors. Our consolidated effective tax rate was 25.7% for the first quarter of 2022, compared to 35.5% for the first quarter of 2021. The higher effective tax rate for the first quarter of 2021 primarily reflects the non-deductibility of losses at our Canadian division, which were driven by exit-related costs associated with Naturalizer retail stores. This impact on the tax rate was partially offset by discrete tax benefits totaling $1.2 million in the first quarter of 2021.