diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/util/TimestampFormatter.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/util/TimestampFormatter.scala
index de2fd312b7db5..8428964d45707 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/util/TimestampFormatter.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/util/TimestampFormatter.scala
@@ -127,16 +127,37 @@ class FractionTimestampFormatter(zoneId: ZoneId)
   override protected lazy val formatter = DateTimeFormatterHelper.fractionFormatter
 
   // The new formatter will omit the trailing 0 in the timestamp string, but the legacy formatter
-  // can't. Here we borrow the code from Spark 2.4 DateTimeUtils.timestampToString to omit the
-  // trailing 0 for the legacy formatter as well.
+  // can't. Here we use the legacy formatter to format the given timestamp up to seconds fractions,
+  // and custom implementation to format the fractional part without trailing zeros.
   override def format(ts: Timestamp): String = {
-    val timestampString = ts.toString
     val formatted = legacyFormatter.format(ts)
-
-    if (timestampString.length > 19 && timestampString.substring(19) != ".0") {
-      formatted + timestampString.substring(19)
-    } else {
+    var nanos = ts.getNanos
+    if (nanos == 0) {
       formatted
+    } else {
+      // Formats non-zero seconds fraction w/o trailing zeros. For example:
+      //   formatted = '2020-05:27 15:55:30'
+      //   nanos = 001234000
+      // Counts the length of the fractional part: 001234000 -> 6
+      var fracLen = 9
+      while (nanos % 10 == 0) {
+        nanos /= 10
+        fracLen -= 1
+      }
+      // Places `nanos` = 1234 after '2020-05:27 15:55:30.'
+      val fracOffset = formatted.length + 1
+      val totalLen = fracOffset + fracLen
+      // The buffer for the final result: '2020-05:27 15:55:30.001234'
+      val buf = new Array[Char](totalLen)
+      formatted.getChars(0, formatted.length, buf, 0)
+      buf(formatted.length) = '.'
+      var i = totalLen
+      do {
+        i -= 1
+        buf(i) = ('0' + (nanos % 10)).toChar
+        nanos /= 10
+      } while (i > fracOffset)
+      new String(buf)
     }
   }
 }
diff --git a/sql/catalyst/src/test/scala/org/apache/spark/sql/util/TimestampFormatterSuite.scala b/sql/catalyst/src/test/scala/org/apache/spark/sql/util/TimestampFormatterSuite.scala
index 4324d3cff63d7..7ff9b46bc6719 100644
--- a/sql/catalyst/src/test/scala/org/apache/spark/sql/util/TimestampFormatterSuite.scala
+++ b/sql/catalyst/src/test/scala/org/apache/spark/sql/util/TimestampFormatterSuite.scala
@@ -135,6 +135,9 @@ class TimestampFormatterSuite extends SparkFunSuite with SQLHelper with Matchers
   test("format fraction of second") {
     val formatter = TimestampFormatter.getFractionFormatter(UTC)
     Seq(
+      -999999 -> "1969-12-31 23:59:59.000001",
+      -999900 -> "1969-12-31 23:59:59.0001",
+      -1 -> "1969-12-31 23:59:59.999999",
       0 -> "1970-01-01 00:00:00",
       1 -> "1970-01-01 00:00:00.000001",
       1000 -> "1970-01-01 00:00:00.001",